CBSE Class 12 Physics Quiz Test

1. Two field lines can never cross each other.

True

False

"If they did, the field at the point of intersection will not have a
unique direction, which is absurd."

Explanation

"If they did, the field at the point of intersection will not have a
unique direction, which is absurd."

2. The angle of incidence corresponding to an angle of refraction ---------, is called the critical angle.

10º

70º

90º

80º

from Snell’s law

Explanation

from Snell’s law

3. T denotes_________

Tesla

Test law

Testla

Teslla

SI unit .

Explanation

SI unit .

4. Do electromagnetic waves carry energy and momentum like other waves?

Yes

No

Electromagnetic waves do carry energy and momentum like other waves. This is supported by the fact that electromagnetic waves can exert pressure on objects, such as in the case of solar sails, where the momentum of photons is transferred to the sail, causing it to move. Additionally, the energy carried by electromagnetic waves can be harnessed and used in various applications, such as in the form of light for illumination or radio waves for communication. Therefore, it can be concluded that electromagnetic waves possess both energy and momentum.

Explanation

Electromagnetic waves do carry energy and momentum like other waves. This is supported by the fact that electromagnetic waves can exert pressure on objects, such as in the case of solar sails, where the momentum of photons is transferred to the sail, causing it to move. Additionally, the energy carried by electromagnetic waves can be harnessed and used in various applications, such as in the form of light for illumination or radio waves for communication. Therefore, it can be concluded that electromagnetic waves possess both energy and momentum.

5. Give example of communication systems

Television broadcast

Microwave links

Satellite communication

All of the above

"Television broadcast, microwave links and satellite communication
are some examples of communication systems that use space wave mode of propagation."

Explanation

"Television broadcast, microwave links and satellite communication
are some examples of communication systems that use space wave mode of propagation."

6. The explanation of the hydrogen atom spectrum provided by Bohr's model

TRUE

False

The explanation of the hydrogen atom spectrum provided by Bohr’s model.

Explanation

The explanation of the hydrogen atom spectrum provided by Bohr’s model.

7. Light is an ------------ wave.

Invisible wave

Radio wave

Short distance wave

Electromagnetic

Maxwell equation led to the remarkable conclusion that light is an electromagnetic wave.

Explanation

Maxwell equation led to the remarkable conclusion that light is an electromagnetic wave.

8. Radiation has dual nature

Wave

Particle

Both A & B

A or B

Radiation has dual nature: wave and particle.

Explanation

Radiation has dual nature: wave and particle.

9. Maxwell's displacement current also called as electric displacement current.

TRUE

FALSE

Maxwell's displacement current is also referred to as electric displacement current. This concept was introduced by James Clerk Maxwell to modify Ampère's law and incorporate the changing electric field in the region between the plates of a charging capacitor.

Explanation

Maxwell's displacement current is also referred to as electric displacement current. This concept was introduced by James Clerk Maxwell to modify Ampère's law and incorporate the changing electric field in the region between the plates of a charging capacitor.

10. "In amplitude modulation the amplitude of the carrier is varied in accordance with the information signal."

True

False

Since it is AMPLITUDE MODULATION

Explanation

Since it is AMPLITUDE MODULATION

11. An oscillating charge is an example of accelerating charge.

TRUE

False

Statement

Explanation

Statement

12. Communication is the act of transmission of--------------

Speech

Data

Video

All of the above

Communication is the act of transmission of information (can be any signal).

Explanation

Communication is the act of transmission of information (can be any signal).

13. At equilibrium, the rate of generation is equal to the rate of recombination of charge carriers.

TRUE

False

At equilibrium, the rate of generation is equal to the rate of recombination of charge carriers. This means that the number of charge carriers being created (generation) is balanced by the number of charge carriers being lost (recombination). In other words, there is a continuous process of charge carriers being created and then recombining, resulting in a stable equilibrium where the rates of generation and recombination are equal.

Explanation

At equilibrium, the rate of generation is equal to the rate of recombination of charge carriers. This means that the number of charge carriers being created (generation) is balanced by the number of charge carriers being lost (recombination). In other words, there is a continuous process of charge carriers being created and then recombining, resulting in a stable equilibrium where the rates of generation and recombination are equal.

14. Sir Arthur Conan Doyle,the creator of the famous detective Sherlock Holmes

TRUE

FALSE

Sir Arthur Conan Doyle (the creator of the famous detective Sherlock Holmes)

Explanation

Sir Arthur Conan Doyle (the creator of the famous detective Sherlock Holmes)

15. A particle is moving in a circular path of radius r. The displacement after half a circle would be:

Zero

πr

2r

2πr

Displacement is the shortest distance between the initial and final positions of a particle. After completing half a circle, the particle's final position is diametrically opposite to its initial position. Therefore, the displacement is equal to the diameter of the circle, which is 2r.

Explanation

Displacement is the shortest distance between the initial and final positions of a particle. After completing half a circle, the particle's final position is diametrically opposite to its initial position. Therefore, the displacement is equal to the diameter of the circle, which is 2r.

16. The difference

is often called the ________ of the circuit

Voltage

Brandwidth

Frequency deviation

In electrical circuits utilizing frequency modulation (FM), the term "frequency deviation" pertains to the variation in frequency from a fixed central frequency or carrier signal. It represents the extent to which the carrier frequency is altered due to modulation by an input signal. For instance, in FM radio broadcasting, the audio signal modulates the carrier frequency, and the magnitude of frequency deviation corresponds to the amplitude of the audio signal, thereby affecting the quality of the transmitted sound. In essence, frequency deviation quantifies how far the carrier frequency strays from its central value, a crucial parameter in FM systems that helps convey information encoded within the signal, such as audio or data.

Explanation

In electrical circuits utilizing frequency modulation (FM), the term "frequency deviation" pertains to the variation in frequency from a fixed central frequency or carrier signal. It represents the extent to which the carrier frequency is altered due to modulation by an input signal. For instance, in FM radio broadcasting, the audio signal modulates the carrier frequency, and the magnitude of frequency deviation corresponds to the amplitude of the audio signal, thereby affecting the quality of the transmitted sound. In essence, frequency deviation quantifies how far the carrier frequency strays from its central value, a crucial parameter in FM systems that helps convey information encoded within the signal, such as audio or data.

17. The important digital circuits performing special logic operations are called --------------gates.

OR

NOT

AND

All the above

The important digital circuits performing special logic operations are called logic gates. These are: OR, AND, NOT, NAND, and NOR gates.

Explanation

The important digital circuits performing special logic operations are called logic gates. These are: OR, AND, NOT, NAND, and NOR gates.

18. The charge q, which tests the effect of a source charge, is called___________

Postive Charge

Negative charge

Auxilary charge

Test charge

The source charge Q must remain at its original location

Explanation

The source charge Q must remain at its original location

19. Two large plane parallel conducting plates separated by a small distance.

Parallel plane capacitors

Serial plate capacitors

Parallel plate capacitors

Serial plane capacitors

A parallel plate capacitor consists of two large plane parallel conducting plates.

Explanation

A parallel plate capacitor consists of two large plane parallel conducting plates.

20. Emf is __________

Electromotive force

Electromagnetic force

Electromechnical force

Electricmechical force

General abbrevation

Explanation

General abbrevation

21. The unit of Magnetic Flux Is-----------

Volt

Weber

Henry

Ohm

based on the units

Explanation

based on the units

22. _______________ offer resistance to the movement of charges which is intermediate between the conductors and insulators.

Dielectric

Nonconductors

Semiconductors

Nonmetals

They have temperature dependent charactertics

Explanation

They have temperature dependent charactertics

23. ----------and----------- bands appear on the screen are called fringes.

Dark,bright

Dim,dark

White,bright

Gray,black

Due to monocolor nature of fringes

Explanation

Due to monocolor nature of fringes

24. Kirchhoff's rules

Junction rule & loop rule

Junctional rule & loop rule

Mesh rule & node rule

Loop rule & node rule

Termed as junction & loop rule.

Explanation

Termed as junction & loop rule.

25. From Maxwell's equations that electric and magnetic fields in an electromagnetic wave are ------- to each other

Normal

Parellel

Perpendicular

Transverse

nature of electromagnetic waves

Explanation

nature of electromagnetic waves

26. Voltage that varies like a sine function with time, is called

Alter voltage

Alternative voltage

Alternating voltage

Alternation voltage

Such a voltage is called alternating voltage (ac voltage)

Explanation

Such a voltage is called alternating voltage (ac voltage)

27. The centres of positive charges and of negative charges lie at the same place,their dipole moment is -----------.

Uncertain

Zero

Not zero

Infinity

In most molecules, the centres of positive charges and of negative charges lie at the same place. Therefore, their dipole moment is zero.

Explanation

In most molecules, the centres of positive charges and of negative charges lie at the same place. Therefore, their dipole moment is zero.

28. An external input is necessary to sustain ac signal in the output for an -------------

Amplifier

Switch

Only switch not amplifier

None of the above

In an amplifier, a sinusoidal input is given which appears as an amplified signal in the output. This means that an external input is necessary to sustain ac signal in theoutput for an amplifier.

Explanation

In an amplifier, a sinusoidal input is given which appears as an amplified signal in the output. This means that an external input is necessary to sustain ac signal in theoutput for an amplifier.

29. In a non-polar molecule, the centres of positive and negative charges coincide.

FALSE

TRUE

Nature of non-polar molecules.

Explanation

Nature of non-polar molecules.

30. The collisions of the electrons occur at regular intervals

False

True

"since, the direction of the velocity of an electron is completely
random."

Explanation

"since, the direction of the velocity of an electron is completely
random."

31. Relaxation time is denoted using---------

σ

τ

λ

ρ

Standard denotion.

Explanation

Standard denotion.

32. The frequency of the incident light was smaller than a certain minimum value, called the____________ frequency.

Thresthold

Thrusthold

Threshold

Freshold

Generally termed as Threshold Frequency

Explanation

Generally termed as Threshold Frequency

33. __________= 1V/A

1℮

1Ω

1ρ

1σ

unit of resistance.

Explanation

unit of resistance.

34. The basic unit of length is harder to define as accurately in a direct way.

TRUE

FALSE

The statement suggests that it is more challenging to define the basic unit of length accurately in a direct manner. This implies that there may be certain complexities or limitations in directly determining the exact measurement of length. Therefore, the answer "TRUE" indicates that the statement is correct in stating that the basic unit of length is harder to define accurately in a direct way.

Explanation

The statement suggests that it is more challenging to define the basic unit of length accurately in a direct manner. This implies that there may be certain complexities or limitations in directly determining the exact measurement of length. Therefore, the answer "TRUE" indicates that the statement is correct in stating that the basic unit of length is harder to define accurately in a direct way.

35. The algebraic sum of changes in potential around any closed loop must be-----

Negative

Positive

Zero

All the above

based on loop rule.

Explanation

based on loop rule.

36. In Rutherford's nuclear model of the atom, the entire ------ charge and most of the mass of the atom are concentrated in the nucleus with the electrons some distance away.

Positive

Negative

Positive and negative

Positive or negative

only positive

Explanation

only positive

37. Lenz's law states When a current in a coil changes, it induces a back emf in the same coil.

TRUE

FALSE

When a current in a coil changes, it induces a back emf in the same coil.

Explanation

When a current in a coil changes, it induces a back emf in the same coil.

38. Electric field is a --------------field, since force is a------------ quantity

Vector,Vector

Scalar,Vector

Vector,Scaler

Scalar,Scalar

"The term field in physics generally refers to a quantity that is
defined at every point in space and may vary from point to point."

Explanation

"The term field in physics generally refers to a quantity that is
defined at every point in space and may vary from point to point."

39. Odd one out

Amplifier

Oscillator

Logic gates

Transistor oscillator

Rest of them are analogue signals.

Explanation

Rest of them are analogue signals.

40. ∆s Denotes---------

Vector area element

Electric field

Electric flux

Electric charge

According to physical quantity it denotes vector area element

Explanation

According to physical quantity it denotes vector area element

41. If the sizes of charged bodies are very small as compared to the distance between time, call as________

Point charges

Positive charge

Source charge

Test charge

we treat them as point charges.

Explanation

we treat them as point charges.

42. The phenomena of -----------was/were explained in a natural and satisfactory way by the wave picture of light.

Interference

Diffraction

Polarisation

All the above

The phenomena of interference, diffraction and polarisation were explained in a natural and satisfactory way by the wave picture of light.

Explanation

The phenomena of interference, diffraction and polarisation were explained in a natural and satisfactory way by the wave picture of light.

43. The Bohr model is applicable to ----------- atoms.

Boron

Helium

Lithium

Hydrogenic

The explanation of the hydrogen atom spectrum provided by Bohr’s model.

Explanation

The explanation of the hydrogen atom spectrum provided by Bohr’s model.

44. The voltage and current are ---------- with each other.

In phase

Out phase

On phase

Some phase

Inphase to each other.

Explanation

Inphase to each other.

45. What are the waves used in radio and television communication system?

Microwaves

Infrared

Radio

Ultraviolet

radio waves are used in radio and television communication systems.

Explanation

radio waves are used in radio and television communication systems.

46. Coulomb force and gravitational force follow the same ----------

Square law

Inverse square law

Inverse law

Newton's law

Coulomb force and gravitational force follow the same inverse-square law

Explanation

Coulomb force and gravitational force follow the same inverse-square law

47. The polarity of induced emf is such that it tends to produce a current which opposes the change in magnetic flux that produced it.

Law of electromagnetic induction

Lenz’s law

Len's law

Motional electromotive law

Lenz's law statement.

Explanation

Lenz's law statement.

48. VECC is------

Variable energy cyclotron center

Variation energy cyclotron center

Variant energy cyclotron center

Various energy cyclotron center

Since the variable energy cyclotron was build in VECC, kolkata.

Explanation

Since the variable energy cyclotron was build in VECC, kolkata.

49. Which one of the following is compound semiconductors?

PI

Cd

Si

Combinedly both B & C

Both Cd (Cadmium) and Si (Silicon) are examples of compound semiconductors. Compound semiconductors are composed of two or more elements, and in the case of Cd, they form compounds with other elements to create semiconductor materials. Silicon, although a group IV element, can also be part of compound semiconductors when combined with elements from other groups, creating various types of semiconducting materials.

Explanation

Both Cd (Cadmium) and Si (Silicon) are examples of compound semiconductors. Compound semiconductors are composed of two or more elements, and in the case of Cd, they form compounds with other elements to create semiconductor materials. Silicon, although a group IV element, can also be part of compound semiconductors when combined with elements from other groups, creating various types of semiconducting materials.

50. The energy required to take out an electron from the atom is called----

Extrinsic energy

Intrinsic energy

Ionisation energy

All the above

Ionization energy is the amount of energy needed to remove an electron from an atom, converting it into a positively charged ion. It is typically expressed in terms of energy per mole of atoms and is often measured in electron volts (eV) or kilojoules per mole (kJ/mol).

Explanation

Ionization energy is the amount of energy needed to remove an electron from an atom, converting it into a positively charged ion. It is typically expressed in terms of energy per mole of atoms and is often measured in electron volts (eV) or kilojoules per mole (kJ/mol).

51. Which one of these is used to measure internel resitance of a cell

Wheatstone bridge

Ammetre

Potentiometre

Metre bridge

For this the cell (emf e ) whose internal resistance (r) is to be determined isconnected across a resistance box through a key K2.

Explanation

For this the cell (emf e ) whose internal resistance (r) is to be determined isconnected across a resistance box through a key K2.

52. Mass number equal to---------------

Z-N

Z+N

Z*N

Z/n

number of protons+number of neutrons

Explanation

number of protons+number of neutrons

53. When fusion is achieved by raising the temperature of the system so that particles have enough kinetic energy to overcome the coulomb repulsive behaviour, it is called ________.

Thermonucleus fusion

Thermonuclear fusion

Thermonicnuclear fusion

Thermoninucleus fusion

The generalised term used hence it is "B"

Explanation

The generalised term used hence it is "B"

54. Ammeter is used to measure ----------.

A

µA

MA

All the above

All denotes various unit of current

Explanation

All denotes various unit of current

55. Coherently illuminated single slit usually called the -------diffraction pattern.

Multiple slit

Single slit

Grouped slit

Join slit

normally known another name.

Explanation

normally known another name.

56. Another phrase commonly used means potential difference between two points?

Flux

Field

Density

Voltage

potential difference between two points also known as voltage.

Explanation

potential difference between two points also known as voltage.

57. Ampere's circuital law holds for----------

Steady current

Steady voltage

Flucuating current

Flucuating voltage

According to ampere circuital alw

Explanation

According to ampere circuital alw

58. It is also possible that emf is induced in a single isolated coil due to change of flux through the coil by means of varying the current through the same coil.

Induction

Self-induction

Mutual induction

Separate induction

This is the phenomenon of self-induction.

Explanation

This is the phenomenon of self-induction.

59. The speed of light is _____________ and _______________

Infinite , Measurable

Finite , Measurable

Finite , Not Measurable

Fine , Measurable

since speed and direction can be determined

Explanation

since speed and direction can be determined

60. What processes the incoming message signal so as to make it suitable for transmission through a channel and subsequent reception

Transducer

Receiver

Transmitter

Repeater

Basic definition of Transmitter

Explanation

Basic definition of Transmitter

61. I/A, is called --------

Current intensity

Magnetic field density

Current density

Magnetic field density

j= I/A (i.e) current density

Explanation

j= I/A (i.e) current density

62. _________nuclides with same mass number A are called isobars

Few

Some

All

More

All nuclides with same mass number A are called isobars

Explanation

All nuclides with same mass number A are called isobars

63. The two displacements are now out of phase and the two displacements will cancel out to give zero intensity. This is referred to as -------------.

Simple interference

Restructive interference

Constructive interference

Destructive interference

since the two displacements will cancel out to give zero intensity. This is referred to as destructive interference.

Explanation

since the two displacements will cancel out to give zero intensity. This is referred to as destructive interference.

64. Does a bar magner exert a torque on itself due to its own field?

Yes

No

There is no force or torque on an element due the field produced by the element itself.

Explanation

There is no force or torque on an element due the field produced by the element itself.

65. AC generator is based on the phenomenon of -----------

Induction

Self-induction

Mutual induction

Electromagnetic induction

principle of AC generator.

Explanation

principle of AC generator.

66. Current is a Vector Quantity

FALSE

TURE

Current is a scalar although we represent current with an arrow.

Explanation

Current is a scalar although we represent current with an arrow.

67. Locus of points, which oscillate in phase is called a -------------

Plane wave

Huygens point

Huygens wave

Wavefront

based on HUYGENS PRINCIPLE

Explanation

based on HUYGENS PRINCIPLE

68. The net----------- through any closed surface is 0

Magnetic flux density

Magnetic field intensity

Magnetic flux

None of the above

based on gauss law.

Explanation

based on gauss law.

69. Each quantum of radiant energy has energy hv, where h is-----------.

Prank’s constant

Planck’s constant

Plank’s constant

Plack’s constant

Each quantum of radiant energy has energy hv, where h is Planck’s constant and n the frequency of light.

Explanation

Each quantum of radiant energy has energy hv, where h is Planck’s constant and n the frequency of light.

70. Isotope means the same place

TRUE

False

In Greek,isotope means the same place

Explanation

In Greek,isotope means the same place

71. A gram of water contains approximately 10^22 ------------

Electrons

Charged nuclei

Atom

Molecules

Bulk matter is made up of many molecules.

Explanation

Bulk matter is made up of many molecules.

72. The pole near the geographic north pole of eath is called the -------

North seeking pole

South magnetic pole

North magnetic pole

North electric pole

The pole near the geographic north pole of the earth is called the north magnetic pole. This is because the north magnetic pole is the point on the earth's surface where the magnetic field lines are directed vertically downwards, indicating the direction towards the earth's magnetic north pole. This is different from the geographic north pole, which is the point on the earth's surface that lies at the northernmost point of the earth's axis of rotation. Therefore, the correct answer is north magnetic pole.

Explanation

The pole near the geographic north pole of the earth is called the north magnetic pole. This is because the north magnetic pole is the point on the earth's surface where the magnetic field lines are directed vertically downwards, indicating the direction towards the earth's magnetic north pole. This is different from the geographic north pole, which is the point on the earth's surface that lies at the northernmost point of the earth's axis of rotation. Therefore, the correct answer is north magnetic pole.

73.

silver is a ---------conductor

Non

Heterogeneous

Non-Homogeneous

Homogeneous

silver consists of homogeneous molecules.

Explanation

silver consists of homogeneous molecules.

74. The cyclotron uses----------- to increase the energy of charged particles.

Electric field

Magnetic field

Magnetostatic field

Both electric &magnetic fields

both electric and magnetic fields in combination is used to increase the energy of charged particles.

Explanation

both electric and magnetic fields in combination is used to increase the energy of charged particles.

75. Marie Sklodowska Curie

Physicist

Chemist

Both A & B

Radioactivist

She is a physicist and as a chemist.

Explanation

She is a physicist and as a chemist.

76. Parallel currents repel, and anti-parallel currents attract.

TRUE

FALSE

In electromagnetism, parallel currents flowing in the same direction create magnetic fields that interact in a way that results in an attractive force between the conductors. Conversely, anti-parallel currents flowing in opposite directions generate magnetic fields that interact to produce a repulsive force between the conductors. This behavior is described by the right-hand rule for the magnetic field around a current-carrying conductor. I appreciate your understanding and patience.

Explanation

In electromagnetism, parallel currents flowing in the same direction create magnetic fields that interact in a way that results in an attractive force between the conductors. Conversely, anti-parallel currents flowing in opposite directions generate magnetic fields that interact to produce a repulsive force between the conductors. This behavior is described by the right-hand rule for the magnetic field around a current-carrying conductor. I appreciate your understanding and patience.

77. Two important processes occur during the formation of a p-n junction:-------- and -----------

Fusion,drift.

Fission,rift

Fusion, rift.

Diffusion,drift.

Two processes namely diffusion and drift

Explanation

Two processes namely diffusion and drift

78. The name electricity is coined from the Greek word __________meaning amber

Elektron

Electron

Electrion

Elektrion

Elektron is a greek word that coins electricity

Explanation

Elektron is a greek word that coins electricity

79. Light of shorter wavelengths is scattered much less than light of longer wavelengths

TRUE

False

Light of shorter wavelengths is scattered much more than light of longer wavelengths

Explanation

Light of shorter wavelengths is scattered much more than light of longer wavelengths

80. The current carried by conductors due to flow of charges is called ----------- current.

Conduction

Conductor

Conducting

Conducted

The current carried by conductors due to flow of charges is called conduction current.

Explanation

The current carried by conductors due to flow of charges is called conduction current.

81. Can we take one slab of p-type semiconductor and physically join it to another n-type semiconductor to get p-n junction?

Yes

No

"No! Any slab, howsoever flat, will have roughness much larger than the inter-atomic crystal spacing and hence continuous ontact at the atomic level will not be possible. The junction
will behave as a discontinuity for the flowing charge carriers."

Explanation

"No! Any slab, howsoever flat, will have roughness much larger than the inter-atomic crystal spacing and hence continuous ontact at the atomic level will not be possible. The junction
will behave as a discontinuity for the flowing charge carriers."

82. The process of addition of a desirable impurity to a semiconductor is called dopant

TRUE

False

The process of adding a desirable impurity to a semiconductor is indeed called doping. Dopants are intentionally introduced into a semiconductor material to modify its electrical properties. Depending on the type of dopant added, the semiconductor can become either n-type or p-type.

Explanation

The process of adding a desirable impurity to a semiconductor is indeed called doping. Dopants are intentionally introduced into a semiconductor material to modify its electrical properties. Depending on the type of dopant added, the semiconductor can become either n-type or p-type.

83. WWW was invented by the ----------------

"AlexanderBain"

Tim Berners-Lee

"J.C.R.Licklider"

Samuel F.B. Morse

Tim Berners-Lee invented the World Wide Web.

Explanation

Tim Berners-Lee invented the World Wide Web.

84. A plane perpendicular to the dipole axis through its centre.

S-plane

Xy plane

Perpendicular plane

Equatorial plane

The equatorial plane of the dipole,i.e., on a plane perpendicular to the dipole axis through its centre.

Explanation

The equatorial plane of the dipole,i.e., on a plane perpendicular to the dipole axis through its centre.

85.

=

This relation is known as______

Mirror equation

Thin lens formula

First focal point formula

Second focal point formula

By applying sign convention in refraction by a lens

Explanation

By applying sign convention in refraction by a lens

86. The magnitude of the induced emf in a circuit is equal to the time rate of change of magnetic flux through the circuit.

Law of electromagnetic induction

Lenz’s law

Conservation of energy

Motional electromotive law

based on faraday's law of electromagnetic induction

Explanation

based on faraday's law of electromagnetic induction

87. Hertz observed that high voltage sparks across the ____ loop were enhanced when the emitter plate was illuminated by ultraviolet light from an arc lamp.

Director

Direction

Detective

Detector

since it is spelled correctly as coined by Hertz.

Explanation

since it is spelled correctly as coined by Hertz.

88. The ------------ and its balance condition provide a practical method for determination of an unknown resistance

Ammetre

Potentiometre

Metre bridge

Wheatstone bridge

It only uses balance condition to find the resistance

Explanation

It only uses balance condition to find the resistance

89. Electromagnetic damping related to

Law of electromagnetic induction

Motional electromotive law

Eddy current

Current law

Application of eddy current

Explanation

Application of eddy current

90. The radius of the circular component of motion is called the radius of the -------.

Rectangular

Circular

Helix

Hyperbola

Due to generic motion

Explanation

Due to generic motion

91. In Biot-Savart's law the relation between --------- and ------- field it produces.

Current & electric

Current & magnetic

Electric & magnetic

Magnetic& dielectric

based on biot savart law's statement

Explanation

based on biot savart law's statement

92. The lens does not introduce any extra path differences in a perpendicular beam

TRUE

FALSE

The lens does not introduce any extra path differences in a parallel beam.

Explanation

The lens does not introduce any extra path differences in a parallel beam.

93. Which is typically the order of magnitude of currents in domestic appliances?

Ampere

Field

Mobility

Voltage

An ampere is defined through magnetic effects of currents

Explanation

An ampere is defined through magnetic effects of currents

94. Young's double slit of separation ----- gives equally spaced fringes of angular separation------- .

D/λ,d

D,λ

D,λ/d

D,dλ

since,The source, mid-point of the slits, and central bright fringe lie in a straight line.

Explanation

since,The source, mid-point of the slits, and central bright fringe lie in a straight line.

95. L

tR

=

Voltage applied to a__________

Series RLC

Parallel LC

Parallel LCR

Series CR

According to AC voltage drived from kirchhoff's loop rule.

Explanation

According to AC voltage drived from kirchhoff's loop rule.

96. Which of these potentials are same?

Negative or retarding

Positive or retaining

Negative or restriking

None of the above

Negative and retarding indicates decreasing

Explanation

Negative and retarding indicates decreasing

97. In ---------- model, an atom is a spherical cloud of positive charges with electrons embedded in it

Rutherford’s

Bohr’s

Thomson’s

Paschen's

based on Thomson’s theory

Explanation

based on Thomson’s theory

98. Light energy is concentrated in tiny particles called _________

Corpuscles

Carpuscles

Corpascles

Corpuscells

Spelled correctly

Explanation

Spelled correctly

99. The ray from the point which is parallel to the principal axis. The reflected ray goes through the ___ of the mirror.

Foci

Principal focus

Principal axis

Focus

Charactersitcs of the wave

Explanation

Charactersitcs of the wave

100. A current or a field (electric or magnetic) emerging out of the plane of the paper is depicted by -----

Dot

Cross

Both dot & cross

Neither cross nor dot

According dot rule.

Explanation

According dot rule.

101. The electric field inside the plates of the capacitor is directed ------- to the plates.

Perpendicular

Parellel

Normal

Transverse

nature of fields

Explanation

nature of fields

102. The secondary of the transformer is provided with a centre tapping and so it is called -------------- transformer.

Middle-tap

Medium-tap

Centre-tap

Central-tap

since, tappings are find at the center of the transformer's secondary.

Explanation

since, tappings are find at the center of the transformer's secondary.

103. For paraxial rays tanø=ø, now tan(n-1)ø=? Consider ø is small

Nø-ø

ø

2ø

Nø

since, tanø=ø then tan(n-1)ø=nø-ø

Explanation

since, tanø=ø then tan(n-1)ø=nø-ø

104. The picture of field lines was invented by Faraday,called---------

Line of Field

Line of force

Line of charge

Line of falls

"The picture of field lines was invented by Faraday to develop an
intuitive non- mathematical way of visualizing electric fields around charged configurations. Faraday called them lines of force."

Explanation

"The picture of field lines was invented by Faraday to develop an
intuitive non- mathematical way of visualizing electric fields around charged configurations. Faraday called them lines of force."

105. Give an example of a material exhibiting behaviour such as relation between V and I is not unique

Glass

Pure water

NaCl

GaAs

In GaAs,there is more than one value of V for the same current I

Explanation

In GaAs,there is more than one value of V for the same current I

106. Another name of Rutherford's planetary model is ----------

Plum pudding model

Nuclear model of the atom

Nucleus model

Bohr's model

he named as the nuclear model of the atom.

Explanation

he named as the nuclear model of the atom.

107. The modern ac generator with a typical output capacity of ------ is a highly evolved machine.

0-50 MW

50-90 MW

90-110MW

30-70 MW

The modern ac generator with a typical output capacity of 100 MW is a highly evolved machine.

Explanation

The modern ac generator with a typical output capacity of 100 MW is a highly evolved machine.

108. A well-known example of alpha decay is the decay of uranium (? ,?) to thorium (A=234 ,Z=90 )

A=234 ,Z=92

A=238 ,Z=92

A=238 ,Z=90

A=239,Z=92

only the selected combination exists.

Explanation

only the selected combination exists.

109. Transverse elastic wave meant --------

Light

Sound

Infrared

Ray

"Transverse elastic (sound) waves can also propagate
in a solid, which is rigid and that resists shear."

Explanation

"Transverse elastic (sound) waves can also propagate
in a solid, which is rigid and that resists shear."

110. Linear Charge density is --,surface Charge density is --,volume Charge density is --.

ρ,λ,σ

λ,ρ,σ

λ,σ,ρ

σ,ρ,λ

conventional symbols

Explanation

conventional symbols

111. Which exhibit a very weak dependence of resistivity with temperature?

Nickel

Pure water

Nichrome

Iron

which is an alloy of nickel, iron and chromium.

Explanation

which is an alloy of nickel, iron and chromium.

112. Which band consist of 4N energy states?

Conduction

Valence

A & B

A or B

The band consisting of 4N energy states,called the conduction band, is completely empty at absolute zero.

Explanation

The band consisting of 4N energy states,called the conduction band, is completely empty at absolute zero.

113. The space-charge region on either side of the junction together is known as ------------- region

Depletion

Diffusion

Depleted

Driftted

space-charge region on either side of the junction together is known as depletion region as the electrons and holes taking part in the initial movement across the junction depleted the region of its free charges

Explanation

space-charge region on either side of the junction together is known as depletion region as the electrons and holes taking part in the initial movement across the junction depleted the region of its free charges

114. A portion of the output power is returned back to the input in phase with the starting power -----------

Positivefeedback

Negativefeedback

Both A & B

A or B

"A portion of the output power is returned back (feedback)
to the input in phase with the starting power (this process is termed positive feedback)"

Explanation

"A portion of the output power is returned back (feedback)
to the input in phase with the starting power (this process is termed positive feedback)"

115. Sound waves in air are latitudinal waves of compression and rarefaction.

TRUE

FALSE

Sound waves in air are longitudinal waves of compression and rarefaction.

Explanation

Sound waves in air are longitudinal waves of compression and rarefaction.

116. Diffraction is a general characteristic exhibited by -----------

Sound waves

Light waves

Matter

All the above

"Diffraction is a general characteristic exhibited by all types of
waves, be it sound waves, light waves, water waves or matter waves"

Explanation

"Diffraction is a general characteristic exhibited by all types of
waves, be it sound waves, light waves, water waves or matter waves"

117. The notion of continuous charge distribution is similar to continuous -------------distribution in mechanics

Inertia

Force

Weight

Mass

we adopt for continuous mass distribution in mechanics

Explanation

we adopt for continuous mass distribution in mechanics

118. The angle between the true geographic north and the north shown by a compass needle.

Magnetic degree

Electric declination

Compass angle

Declination

The angle between them is called magentic declination or simply declination.

Explanation

The angle between them is called magentic declination or simply declination.

119. Kirchhoff's --------- is based on conservation of charge

Loop rule

Junction rule

Loop & junction rule

Either junction or loop rule

since Bending or reorienting the wire does not change the validity of Kirchhoff’s junction rule.

Explanation

since Bending or reorienting the wire does not change the validity of Kirchhoff’s junction rule.

120. A set of equations involving magnetic field, and their sources, the charge and current densities are known as Maxwell's equations.

TRUE

FALSE

Maxwell formulated a set of equations involves both electric and magnetic fields,

Explanation

Maxwell formulated a set of equations involves both electric and magnetic fields,

121. Which band is completely empty at absolute zero?

Conduction

Valence

A & B

A or B

The band consisting of 4N energy states,called the conduction band, is completely empty at absolute zero.

Explanation

The band consisting of 4N energy states,called the conduction band, is completely empty at absolute zero.

122. Maxwell showed,a changing electric field must also produce a magnetic flux.

TRUE

FALSE

Maxwell showed that for logical consistency, a changing electric field must also produce a magnetic field.

Explanation

Maxwell showed that for logical consistency, a changing electric field must also produce a magnetic field.

123. The reflected rays converge at a point F on the _______ of a concave mirror

Focus

Paraxial

Foci

Principal axis

Due to the concave nature of the mirror

Explanation

Due to the concave nature of the mirror

124. In -------- and---------, light energy is redistributed

Interference,diffraction

Refraction, diffraction

Reflection,diffraction,

Polarisation,diffraction

based on single slit diffraction pattern.

Explanation

based on single slit diffraction pattern.

125. The number of photoelectrons emitted per second is directly proportional to the intensity of ______.

Photoelctric emission

Incident radiation

Threshold frequency

Field emission

The photocurrent is directly proportional to the number of photoelectrons emitted per second. This implies that the number of photoelectrons emitted per second is directly proportional to the intensity of incident radiation.

Explanation

The photocurrent is directly proportional to the number of photoelectrons emitted per second. This implies that the number of photoelectrons emitted per second is directly proportional to the intensity of incident radiation.

126. For a frequency of incident radiation, lower than the cut-off frequency, no photoelectric emission is possible even if the intensity is ------------.

Small

Medium

Large

Extra-large

Based on the observation of Effect of frequency of incident radiation on stopping potential

Explanation

Based on the observation of Effect of frequency of incident radiation on stopping potential

127. An electron in an atom could revolve in certain stable orbits without the emission of radiant energy

Bohr’s first postulate

Bohr’s second postulate

Bohr’s thrid postulate

Bohr’s forth postulate

According to his postulate.

Explanation

According to his postulate.

128. Root Mean Square is also called -----------

Mean current

Effective current

Efficient current

Effect current

RMS Is also called effective current.

Explanation

RMS Is also called effective current.

129. Electromagnetic waves are ---- of electric and magnetic fields in free space, or vacuum.

Self-subtaining oscillations

Self-retaining oscillations

Self-obtaining oscillations

Self-sustaining oscillations

Electromagnetic waves are self-sustaining oscillations of electric and magnetic fields in free space, or vacuum. This means that the electric and magnetic fields are able to propagate through space without the need for any external source of energy or support. The term "self-sustaining" implies that the oscillations can continue indefinitely without any external input.

Explanation

Electromagnetic waves are self-sustaining oscillations of electric and magnetic fields in free space, or vacuum. This means that the electric and magnetic fields are able to propagate through space without the need for any external source of energy or support. The term "self-sustaining" implies that the oscillations can continue indefinitely without any external input.

130. What allows transfer of files/software from one computer to another connected to the Internet?

HTTP

FTP

TCP

IP

FTP (File Transfer Programmes)

Explanation

FTP (File Transfer Programmes)

131. Frequencies in the UHF range normally propagate by means of:

Ground waves

Sky waves

Surface waves

Space waves

Frequency bands UHF174-216 MHz

Explanation

Frequency bands UHF174-216 MHz

132. Which of the following is debroglie wavelength?

M

H/m

Matter wave

Both a&b

The wavelength λ of the matter wave is called de Broglie wavelength

Explanation

The wavelength λ of the matter wave is called de Broglie wavelength

133. Power of a lens is a measure of the------------

Convergence or divergence

Convergence and divergence

Convergence on divergence

Convergence in divergence

Definition of power of lens

Explanation

Definition of power of lens

134. Frequency band of Satellite Communication is ---------------------

540-1600 kHz

3.7-4.2 GHz

88-108 MHz

420-890 MHz

Frequency band of Satellite Communication

Explanation

Frequency band of Satellite Communication

135. The de Broglie hypothesis has been basic to the development of modern -----------------

Quantum mechanics

De Broglie relation

"Davisson-Germer experiment"

Wave nature of light

The de Broglie hypothesis has been basic to the development of modern quantum mechanics. It has also led to the field of electron optics

Explanation

The de Broglie hypothesis has been basic to the development of modern quantum mechanics. It has also led to the field of electron optics

136. Minimum energy required by an electron to escape from the metal surface is called the ________ of the metal.

Incident Frequency

Threshold Frequency

Work function

Freshold Frequency

Minimum Energy denotes Work function.

Explanation

Minimum Energy denotes Work function.

137.

Reactance diagram

Impedance diagram

Capacitance diagram

Phasor diagram

denotes impedance.

Explanation

denotes impedance.

138. "A TV signal contains both voice and picture and is usually allocated 16 MHz of bandwidth for transmission."

TRUE

False

"A TV signal contains both voice and picture and is usually
allocated 6 MHz of bandwidth for transmission."

Explanation

"A TV signal contains both voice and picture and is usually
allocated 6 MHz of bandwidth for transmission."

139. Magetic field lines show the direction (at every point) along which a small magnetised needle aligns (at the point). Do the magnet field lines also represent the lines of force on a moving charged particle at every point?

Yes

NO

The magnet force is always normal to B.

Explanation

The magnet force is always normal to B.

140. The solution of the Schrödinger wave equation, obtained for hydrogen-like atoms/ ions, called the wave function, gives nformation about the probability of finding an electron in various regions around the nucleus. This ---- has no resemblance whatsoever with the ---------- defined for an electron in the Bohr model.

Orbitration,orbit

Orbit,orbital

Orbital,orbit

Orbit,orbitration

ORBIT VS STATE OF ELECTRON IN ATOM

Explanation

ORBIT VS STATE OF ELECTRON IN ATOM

141. Photons are electrically ------------ and are ----------- by electric and magnetic fields.

Neutral,not deflected

Positive, deflected

Negative,not deflected

Neutral, deflected

based on the characteristics of photon picture of electromagnteic radiation.

Explanation

based on the characteristics of photon picture of electromagnteic radiation.

142. The energy associated with thepropagating wave comes at the expense of the energy of the source – theaccelerated wave.

TRUE

FALSE

The energy associated with the propagating wave comes at the expense of the energy of the source – the accelerated charge.

Explanation

The energy associated with the propagating wave comes at the expense of the energy of the source – the accelerated charge.

143. The total current passing through any surface of which the closed loop is the perimeter. This generalized law is known as-------

Ampere- maxwell law

Ampere law

Maxwell law

Faraday's law

The statement describes the Ampère-Maxwell law, a generalization of Ampère's Law. The Ampère-Maxwell law includes the displacement current term, which James Clerk Maxwell added to Ampère's Law to make the equation consistent with the principle of conservation of charge. This law is a fundamental equation in electromagnetism that describes how magnetic fields are generated both by electric currents and by changing electric fields.

Explanation

The statement describes the Ampère-Maxwell law, a generalization of Ampère's Law. The Ampère-Maxwell law includes the displacement current term, which James Clerk Maxwell added to Ampère's Law to make the equation consistent with the principle of conservation of charge. This law is a fundamental equation in electromagnetism that describes how magnetic fields are generated both by electric currents and by changing electric fields.

144. How many basic modes of communication are there?

1

2

3

4

There are two basic modes of communication: point-to-point and broadcast

Explanation

There are two basic modes of communication: point-to-point and broadcast

145. Energy greater than the ---------- required for electron emission from the metal surface can be supplied by suitably heating or applying strong electric field or irradiating it by light of suitable frequency

Incident Frequency

Work function

Threshold Frequency

Freshold Frequency

The minimum energy needed by an electron to come out from a metal surface is called the work function of the metal

Explanation

The minimum energy needed by an electron to come out from a metal surface is called the work function of the metal

146. First model of atom (by J.J.Thomson )was picturesquely called-------- of the atom.

Pudding plum model

Pudded plum model

Putting plum model

None of the above

he named his model as plum pudding model.

Explanation

he named his model as plum pudding model.

147. When the antenna is turned ------- the signal will be greatly diminished.

Vertical

Horizontal

Perpendicular

Parallel

The signal will be greatly diminished,When the antenna is turned horizontal.

Explanation

The signal will be greatly diminished,When the antenna is turned horizontal.

148. The idea of FAX transmission was patented by Alexander Bain in -----------.

1843

1844

1845

1846

Historical event

Explanation

Historical event

149. The resembalance of magnertic field lines for abar magnet and a ------------- suggest that a bar magnet may be thought of as a large number of circulating current in analogy with a ----------. HINT:bar magnet as an equalent solenoid.

Solenoid, toroid

Toroid,toroid

Solenoid,solenoid

Toroid, solenoid

bar magnet as an equalent solenoid.

Explanation

bar magnet as an equalent solenoid.

150. Meissner effect, diamagnetism in --------------

Semi conductors

Super conductors

Conductors

Dielectrics

The Meissner effect is a phenomenon observed in superconductors, where they exhibit perfect diamagnetism, meaning they repel magnetic fields. This effect occurs when a superconductor is cooled below its critical temperature and becomes a perfect conductor of electricity. In contrast, semiconductors, conductors, and dielectrics do not exhibit the Meissner effect or perfect diamagnetism. Therefore, the correct answer is superconductors.

Explanation

The Meissner effect is a phenomenon observed in superconductors, where they exhibit perfect diamagnetism, meaning they repel magnetic fields. This effect occurs when a superconductor is cooled below its critical temperature and becomes a perfect conductor of electricity. In contrast, semiconductors, conductors, and dielectrics do not exhibit the Meissner effect or perfect diamagnetism. Therefore, the correct answer is superconductors.

151. Davisson-Germer's photoelectric equation is in accordance with the energy conservation law as applied to the photon absorption by an electron in the metal.

TRUE

False

Einstein’s photoelectric equation is in accordance with the energy conservation law as applied to the photon absorption by an electron in the metal.

Explanation

Einstein’s photoelectric equation is in accordance with the energy conservation law as applied to the photon absorption by an electron in the metal.

152. The SI unit for activity is becquerel, named after the discoverer of radioactivity.

A.Henry Becquerel

E.Henry Becquerel

O.Henry Becquerel

None of the above

his name is , A.Henry Becquerel or , A.H. Becquerel

Explanation

his name is , A.Henry Becquerel or , A.H. Becquerel

153. CRT used in television and computer monitors, which work on the principle of vacuum tubes, are being replaced by LCD monitors with supporting Liquid-state electronics.

TRUE

False

Cathode Ray Tubes (CRT) used in television and computer monitors, which work on the principle of vacuum tubes, are being replaced by Liquid Crystal Display (LCD) monitors with supporting solid-state electronics.

Explanation

Cathode Ray Tubes (CRT) used in television and computer monitors, which work on the principle of vacuum tubes, are being replaced by Liquid Crystal Display (LCD) monitors with supporting solid-state electronics.

154. Frequency band for cellulor mobile radio(base station to mobile)

839MHz

936MHz

940MHz

845MHz

based on the frequency bands standard bandwidth.

Explanation

based on the frequency bands standard bandwidth.

155. The volume charge density also called as -----------

Field density

Volume density

Charge density

Charged density

sometimes simply called charge density

Explanation

sometimes simply called charge density

156. A basic law regarding flow of currents was discovered by------------in 1828, long before the physical mechanism responsible for flow of currentswas discovered.

Faraday

G.S. Ohm

Van de Graff

Kirchoff

based on ohm's bibliography

Explanation

based on ohm's bibliography

157. By applying a very strong electric field to a metal, electrons can be pulled out of the metal, as in a spark plug.

Field emission

Thermionic emission

Photo-electric emission

Photo-electrical emission

Definition of Field emission.

Explanation

Definition of Field emission.

158. The existence of discrete energy levels in an atom was directly verified in 1914 by ---------- and ---------.

Gustav Hertz,James Franck

James Franck, Gustav Hertz

Gustav Franck,James Hertz

Franck Hertz, Gustav James

correct order of their names.

Explanation

correct order of their names.

159. In cyclotron, as the fields are perpendicular to each other are called ------------

Perpendicular field

Crossed fields

Cyclotron field

Magnetic field

There are generally called as crossed fields.

Explanation

There are generally called as crossed fields.

160. The phasors V and I ( for resistor) are in same phase. This mean that the phase angle is --------

90 degree

180 degree

360 degree

45 degree

That the phase angle between the voltage and the current is zero.

Explanation

That the phase angle between the voltage and the current is zero.

161. The atomic energy programme in India was launched around the time of independence under the leadership of Homi G. Bhabha

TRUE

False

His name is Homi J. Bhabha

Explanation

His name is Homi J. Bhabha

162. What is the phenomenon where light bends around the edge of an obstacle or through a slit, resulting in patterns of light and dark bands?

Refraction

Diffraction

Polarization

Dispersion

Diffraction occurs when waves encounter an obstacle or a slit that is comparable in size to their wavelength. For light, this leads to bending around the edges and the formation of a pattern of interference bands. Diffraction is distinct from refraction, which involves the bending of light as it passes from one medium to another, and polarization, which is related to the orientation of light waves. Diffraction is fundamental in explaining behaviors of waves that cannot be accounted for by geometrical optics alone.

Explanation

Diffraction occurs when waves encounter an obstacle or a slit that is comparable in size to their wavelength. For light, this leads to bending around the edges and the formation of a pattern of interference bands. Diffraction is distinct from refraction, which involves the bending of light as it passes from one medium to another, and polarization, which is related to the orientation of light waves. Diffraction is fundamental in explaining behaviors of waves that cannot be accounted for by geometrical optics alone.

163. Which is used for detecting optical signals?

Detectors

Photodirectors

Photodiods

All of the above

Photodiodes used for detecting optical signal (photodetectors).

Explanation

Photodiodes used for detecting optical signal (photodetectors).

164. The basic unit of time can be defined very accurately in terms of some ----------

Oscillating frequency

Oscillating charge

Atomic frequency

Atomic charge

frequency of light emitted by an atom in a particular process.

Explanation

frequency of light emitted by an atom in a particular process.

165. Which of the following frequencies will be suitable for beyond-thehorizon communication using sky waves?

10 kHz

10 MHz

1 GHz

1000 GHz

"10 kHz cannot be radiated (antenna size), 1 GHz and 1000 GHz
will penetrate."

Explanation

"10 kHz cannot be radiated (antenna size), 1 GHz and 1000 GHz
will penetrate."

166. Coulomb used a torsion balance. A torsion balance is a sensitive device to measure ________.

Charge

Elecricity

Polarity

Force

Coulomb used torsion balance only for measuring the force between two charged metallic spheres

Explanation

Coulomb used torsion balance only for measuring the force between two charged metallic spheres

167. "The electric field due to a charge configuration with total charge zero is not zero; but for distances large compared to the size of the configuration, its field falls off faster than 1/r2, typical of field due to a single charge".Give example for above fact.

Electric charge

Electirc density

Electric dipole moment

Electric dipole

An electric dipole is the simplest example

Explanation

An electric dipole is the simplest example

168. The magnet field lines gives us an approximate idea of the magnetic field B.

Pattern of electric fillings

Pattern of magnetic fillings

Pattern of dipole fillings

Pattern of iron fillings

A dipole in an uniform magnetic field.

Explanation

A dipole in an uniform magnetic field.

169. Millikan's ---------- precise measurements confirmed the Einstein's photoelectric equation and obtained an accurate value of Planck's constant h

First

Second

Thrid

Last

confirmed at his first experiment.

Explanation

confirmed at his first experiment.

170. A photocell is a technological application of the photoelectric electrons.

TRUE

FALSE

A photocell is a technological application of the photoelectric effect.

Explanation

A photocell is a technological application of the photoelectric effect.

171. The phenomenon of resonance is common among systems that have a tendency to oscillate at a particular frequency.

Natural frequency

Resonance

Resonant

Ordinary frequency

This frequency is called the system’s natural frequency

Explanation

This frequency is called the system’s natural frequency

172. An electromagnetic wave also exerts -------

Radiation temperature

Radiation wave

Radiation velocity

Radiation pressure

Since it carries momentum, an electromagnetic wave also exerts pressure,called radiation pressure.

Explanation

Since it carries momentum, an electromagnetic wave also exerts pressure,called radiation pressure.

173. IF is --------------- than the carrier frequency

Lower

Slower

Faster

Greater

The carrier frequency is usually changed to a lower frequency by what is called an intermediate frequency (IF)

Explanation

The carrier frequency is usually changed to a lower frequency by what is called an intermediate frequency (IF)

174. The degree of _____________ is an indicator of the amount of charge.

Polarity

Divergence

Positive charge

Negative charge

When a charged object touches the metal knob at the top of the rod, charge flows on to the leaves and they

Explanation

When a charged object touches the metal knob at the top of the rod, charge flows on to the leaves and they

175. Externel field: torque (in-terms of electrostatics)---------,externel field:energy(in-terms of magnetism)------.

PE,-B

PE,-E

MB,-E

PE,mB

By use of dipole analogy.

Explanation

By use of dipole analogy.

176. The dimension of --------- reactance is the same as that of resistance

Inductive

Capacitance

Inductance

Capacitive

The dimension of capacitive reactance is the same as that of resistance and its SI unit is ohm.

Explanation

The dimension of capacitive reactance is the same as that of resistance and its SI unit is ohm.

177. Television uses the --------- to generate the magnetic fields needed.

Toroid or solenoid

Both solenoid & toroid

Toroid

Solenoid

Television only uses solenoid.

Explanation

Television only uses solenoid.

178. Approximate height of Mesosphere over earth's surface is

50-85km

170-190km

30-40km

100-150km

It lies between the range of 50-85km i.e. 31-53 miles.

Explanation

It lies between the range of 50-85km i.e. 31-53 miles.

179. The sun is -----------.This means the electric vector takes all possible directions in the transverse plane, rapidly and randomly, during a measurement.

Equally polarised

Equally unpolarised

Polarised

Unpolarised

since it is a natural light.

Explanation

since it is a natural light.

180. State Ohmic loss

VxI

I^2 x R

IV∆t

IxR

Using ohm's law P=I^2 x R

Explanation

Using ohm's law P=I^2 x R

181. Even when bulk pieces of conductors are subjected to changing magnetic flux, --------- are produced in them

Induced flux

Induced emf

Induced magnetic field

Induced currents

from EDDY CURRENTS statement

Explanation

from EDDY CURRENTS statement

182. The ----------- is much weaker than even --------------.

Gravitational force,Coulomb force

Coulomb force,gravitational force

Nucleus force,gravitational force

Gravitational force,nucleus force

The gravitational force is much weaker than even Coulomb force.

Explanation

The gravitational force is much weaker than even Coulomb force.

183. The field of the electric dipole is--------

Zero

Notzero

Uncertain

Infinity

The total charge of the electric dipole is obviously zero. This does notmean that the field of the electric dipole is zero

Explanation

The total charge of the electric dipole is obviously zero. This does notmean that the field of the electric dipole is zero

184. The cathode rays were discovered, in 1870, by ____ who later, in 1879, suggested that these rays consisted of streams of fast moving negatively charged particles.

J W Crookes

"WilliamCrookes"

J J Thomson

G J Thomson

correctness of author name is selected.

Explanation

correctness of author name is selected.

185. What cable is a widely used wire medium, which offers a bandwidth of approximately 750 MHz?

Fibre

Optic

Coaxial

Fiber optic

Because Coaxial cables are normally operated below 18 GHz.

Explanation

Because Coaxial cables are normally operated below 18 GHz.

186. The wave nature of electrons was first experimentally verified by --------------- and ------------- in 1927 and independently by ------------, in 1928, who observed diffraction effects with beam of electrons scattered by crystals

J.J. Thomson,L.J. Davisson,C.H. Germer.

J.J. Thomson,C.J. Davisson,L.H. Germer.

L.H. Germer,J.J. Thomson,C.J.Davisson

C.J. Davisson,L.H. Germer,G.P. Thomson

The wave nature of electrons was first experimentally verified by C.J.Davisson and L.H. Germer in 1927 and independently by G.P. Thomson, in 1928, who observeddiffraction effects with beams of electrons scattered by crystals.

Explanation

The wave nature of electrons was first experimentally verified by C.J.Davisson and L.H. Germer in 1927 and independently by G.P. Thomson, in 1928, who observeddiffraction effects with beams of electrons scattered by crystals.

187. Insulators have:

High resistivity

Low conductivity

High conductance

Both A & B

They have high resistivity (or low conductivity). Some of the examples of insulators are rubber, glass, graphite, plastics, etc.

Explanation

They have high resistivity (or low conductivity). Some of the examples of insulators are rubber, glass, graphite, plastics, etc.

188. Which type of wave propagation is used by short wave broadcast services?

Sky

Ground

Space

None of the above

sky wave propagation is used by short wave broadcast services.

Explanation

sky wave propagation is used by short wave broadcast services.

189. Which is the process of recovering the modulating signal from an amplitude modulated waveform, is carried out using a rectifier and an envelope detector?

AM detection

Amplitude Modulation

Frequency Modulation

Pulse modulation

AM detection, which is the process of recovering the modulating signal from an AM waveform, is carried out using a rectifier and an envelope detector.

Explanation

AM detection, which is the process of recovering the modulating signal from an AM waveform, is carried out using a rectifier and an envelope detector.

190. Astronomers call the increase in wavelength due to doppler effect as -----------

Green shift

Blue shift

Red shift

Black shift

Astronomers call the increase in wavelength due to doppler effect as red shift since a wavelength in the middle of the visible region of the spectrum moves towards the red end of the spectrum.

Explanation

Astronomers call the increase in wavelength due to doppler effect as red shift since a wavelength in the middle of the visible region of the spectrum moves towards the red end of the spectrum.

191. Who built the first point-contact transistor? (check all that apply)

W.H. Bardeen

J. Bardeen

W.H. Brattain

J.Brattain

The inventors are J. Bardeen and W.H. Brattain of Bell Telephone Laboratories, U.S.A.

Explanation

The inventors are J. Bardeen and W.H. Brattain of Bell Telephone Laboratories, U.S.A.

Submit

192. Which type of wave propagation is used for satellite communication?

LOS

Sky

Ground

Neither A or B

"Space waves are used for line-of-sight (LOS) communication as
well as satellite communication"

Explanation

"Space waves are used for line-of-sight (LOS) communication as
well as satellite communication"

193. Superposition principle,there are ----additional three-body, four-body, etc., forces which arise only when there are more than two charges

Few

No

More

None of the above

Based on Superposition principle.

Explanation

Based on Superposition principle.

194. The self-inductance plays the role of ----------

Inertia

Momentum

Induction

Mutual induction

Physically, the self-inductance plays the role of inertia. It is the electromagnetic analogue of mass in mechanics.

Explanation

Physically, the self-inductance plays the role of inertia. It is the electromagnetic analogue of mass in mechanics.

195. "The binding energy per nucleon is a constant and is approximately equal to ------"

Ek

Ck

Pk

"Since most of the nucleons in a large nucleus reside inside it
and not on the surface, the change in binding energy per nucleon would be small."

Explanation

"Since most of the nucleons in a large nucleus reside inside it
and not on the surface, the change in binding energy per nucleon would be small."

196. According to amperain loop, B is -----------

Only tangential

Only normal

Tangential or normal

Both tangential and normal

based on assumption made in amperian loop B is tangetial or normal or vanish.

Explanation

based on assumption made in amperian loop B is tangetial or normal or vanish.

197. Which is not pulse modulation type

PDM

PAM

PFM

PPM

Pulse Amplitude Modulation (PAM), Pulse Frequency Modulation (PFM), and Pulse Position Modulation (PPM) are all recognized forms of pulse modulation used in communication systems and signal processing.

Pulse Density Modulation (PDM) is a type of modulation where the relative density of pulses corresponds to the analog signal's amplitude. It is commonly used in digital audio applications, particularly in converting analog signals to digital form. While it shares similarities with other pulse modulation techniques, it is not as widely recognized or used in general communication systems compared to PAM, PFM, and PPM. Therefore, PDM is not typically considered a common type of pulse modulation.

Explanation

Pulse Amplitude Modulation (PAM), Pulse Frequency Modulation (PFM), and Pulse Position Modulation (PPM) are all recognized forms of pulse modulation used in communication systems and signal processing.

Pulse Density Modulation (PDM) is a type of modulation where the relative density of pulses corresponds to the analog signal's amplitude. It is commonly used in digital audio applications, particularly in converting analog signals to digital form. While it shares similarities with other pulse modulation techniques, it is not as widely recognized or used in general communication systems compared to PAM, PFM, and PPM. Therefore, PDM is not typically considered a common type of pulse modulation.