1.
What is Cathode Ray?
Correct Answer
B. Beta-ray
Explanation
A cathode ray refers to a beam of electrons that are emitted from the negative electrode, or cathode, in a vacuum tube. These electrons are accelerated towards a positively charged anode and create a visible beam of light. Beta rays, which are high-energy electrons or positrons, are a type of cathode ray. Therefore, the correct answer is beta-ray.
2.
Who discovered Electron?
Correct Answer
D. J. J. Thomson
Explanation
J. J. Thomson discovered the electron. He conducted experiments using cathode ray tubes and observed that they emitted negatively charged particles. He concluded that these particles were fundamental units of electricity, which he named electrons. Thomson's discovery of the electron revolutionized the understanding of atomic structure and laid the foundation for the development of modern physics.
3.
What is the polarity of Anode
Correct Answer
B. Positive
Explanation
The anode is the positively charged electrode in an electrochemical cell or device. It attracts the negatively charged ions or electrons and is where oxidation occurs. Therefore, the correct answer is positive.
4.
What is the polarity of Cathode
Correct Answer
A. Negative
Explanation
The polarity of the cathode is negative because it is the electrode where electrons are received or reduction occurs in an electrochemical cell or device. The cathode attracts positively charged ions or cations and is connected to the negative terminal of a power source.
5.
What is 1 Torr of pressure
Correct Answer
C. 1mm of Hg
Explanation
1 Torr of pressure is equivalent to 1mm of Hg. Torr is a unit of pressure named after Evangelista Torricelli, who invented the mercury barometer. It is defined as the pressure exerted by a column of mercury 1mm high, hence 1mm of Hg. This measurement is commonly used in scientific and medical fields to quantify low pressures.
6.
What is the Pressure in a Vacuum-Tube?
Correct Answer
D. 1 micron of Hg
Explanation
The correct answer is 1 micron of Hg. In a vacuum tube, the pressure is extremely low, and it is commonly measured in microns of mercury (Hg). A micron is a unit of length equal to one millionth of a meter. This indicates that the pressure in a vacuum tube is extremely low, as it is measured in such a small unit of measurement.
7.
What is the charge of electron?
Correct Answer
B. =-1.6*10^-19
Explanation
The charge of an electron is -1.6*10^-19. This value represents the fundamental unit of negative electric charge carried by an electron. The negative sign indicates that electrons have a negative charge, while protons, which have an equal but opposite charge, have a positive charge. The magnitude of the charge, 1.6*10^-19, is extremely small but plays a crucial role in determining the behavior of atoms and the interactions between particles in the field of electromagnetism.
8.
What is the spin of electron?
Correct Answer
B. (1/2)(h/2pi)
Explanation
The spin of an electron is a fundamental property that describes its intrinsic angular momentum. It is quantized and can have two possible values: +1/2 or -1/2, represented as (1/2)(h/2pi) or (-1/2)(h/2pi), respectively. Therefore, the correct answer is (1/2)(h/2pi).
9.
What Statistics is followed by electron?
Correct Answer
B. Fermi-Dirac
Explanation
Fermi-Dirac statistics is followed by electrons. This statistical model describes the behavior of particles with half-integer spin, such as electrons, in a system with many available energy levels. It determines the probability distribution of these particles occupying different energy levels, taking into account the Pauli exclusion principle, which states that no two identical fermions can occupy the same quantum state simultaneously. Therefore, electrons, being fermions, follow Fermi-Dirac statistics.
10.
What are the no. Of elements in a Diode?
Correct Answer
C. 3
Explanation
A diode is a two-terminal electronic component that allows current to flow in only one direction. It consists of three layers: an N-type semiconductor, a P-type semiconductor, and a junction between them. The question is asking for the number of elements in a diode, which refers to the number of layers or components it is made up of. Therefore, the correct answer is 3, as a diode consists of three elements or layers.
11.
What is the function of filament in a VT?
Correct Answer
B. To cause thermionic emission
Explanation
The function of the filament in a VT (vacuum tube) is to cause thermionic emission. Thermionic emission refers to the process of releasing electrons from a heated filament. When the filament is heated, it becomes hot enough to cause the electrons to escape and create a flow of current within the vacuum tube. This is an essential function of the filament as it allows the vacuum tube to conduct electricity and perform its intended purpose.
12.
What is the function of Cathode in VT?
Correct Answer
B. To emit electrons
Explanation
The function of the cathode in a vacuum tube (VT) is to emit electrons. The cathode is heated, causing it to release electrons through a process called thermionic emission. These emitted electrons are then attracted towards the anode, creating a flow of current within the vacuum tube. Therefore, the cathode plays a crucial role in the operation of a VT by generating the electron flow necessary for its functioning.
13.
What is the function of Anode in VT?
Correct Answer
C. To capture electrons
Explanation
The function of the anode in VT (vacuum tubes) is to capture electrons. In a vacuum tube, the anode is a positively charged electrode that attracts and collects the electrons emitted by the cathode. This process allows for the flow of current and the amplification of signals in electronic devices such as radios and televisions.
14.
What is the number of electrodes in Pentode
Correct Answer
A. 5
Explanation
A pentode is a type of vacuum tube that consists of five electrodes. These electrodes are the cathode, control grid, screen grid, suppressor grid, and plate. Each electrode serves a specific function in the amplification and control of the electron flow within the tube. Therefore, the correct answer is 5.
15.
What is the number of electrodes in TRIODE
Correct Answer
B. 3
Explanation
A triode is a type of vacuum tube that contains three electrodes - a cathode, an anode, and a control grid. The cathode emits electrons, the anode collects them, and the control grid regulates the flow of electrons. Therefore, the correct answer is 3.
16.
What is the number of electrodes in TETRODE
Correct Answer
C. 4
Explanation
A tetrode is a type of vacuum tube that contains four electrodes: a cathode, a control grid, a screen grid, and a plate. These electrodes are used to control the flow of electrons within the tube and amplify electrical signals. Therefore, the correct answer is 4.
17.
What is the unit of resistance?
Correct Answer
A. Ohms
Explanation
The unit of resistance is Ohms. Ohms is the standard unit of electrical resistance in the International System of Units (SI). It is named after the German physicist Georg Simon Ohm, who formulated Ohm's law. Resistance is a measure of how much a material or device opposes the flow of electric current. It is represented by the symbol Ω (omega). Henry is the unit of inductance, Farad is the unit of capacitance, and Radians is the unit of angular measurement.
18.
What is the unit of current?
Correct Answer
B. Coul/sec=Ampere
Explanation
The unit of current is Ampere, which is represented by the symbol A. Ampere is defined as one coulomb of charge passing through a point in one second. Therefore, the correct answer is Coul/sec=Ampere.
19.
What is the unit of capacitance ?
Correct Answer
C. Farad
Explanation
The unit of capacitance is the Farad. The Farad is a unit of electrical capacitance, measuring the ability of a capacitor to store an electric charge. It is named after the English physicist Michael Faraday.
20.
What is the unit of Inductor ?
Correct Answer
B. Henry
Explanation
The unit of inductor is Henry. An inductor is a passive electronic component that stores energy in its magnetic field when an electric current flows through it. The unit Henry is named after Joseph Henry, an American scientist who made significant contributions to the study of electromagnetism. It represents the amount of inductance, which is a measure of how much magnetic flux is generated for a given current.
21.
What is the unit of energy ?
Correct Answer
B. Joules
Explanation
Joules is the correct answer for the unit of energy. Energy is measured in joules, which is a derived unit in the International System of Units (SI). It is named after James Prescott Joule, a British physicist who made significant contributions to the study of energy. The joule is defined as the amount of energy transferred when a force of one newton is applied over a distance of one meter. It is commonly used to measure various forms of energy such as mechanical, electrical, and thermal energy.
22.
What is 1 eV of energy?
Correct Answer
D. 1.6*10^-19Joules
Explanation
1 eV of energy is equal to 1.6*10^-19 Joules. The electronvolt (eV) is a unit of energy commonly used in atomic and nuclear physics. It represents the amount of energy gained or lost by an electron when it moves through an electric potential difference of 1 volt. The conversion factor between eV and Joules is 1 eV = 1.6*10^-19 Joules. Therefore, 1 eV is equal to 1.6*10^-19 Joules.
23.
When 1 Coulomb of Charge falls through 1V
Correct Answer
B. 1J gained
Explanation
When 1 Coulomb of charge falls through 1V, 1J of energy is gained. This is because the energy gained or lost by a charged particle can be calculated using the equation E = QV, where E is the energy, Q is the charge, and V is the potential difference. In this case, the charge is 1 Coulomb and the potential difference is 1V, so the energy gained is 1J.
24.
1V into 1 Amp is equal to
Correct Answer
B. 1 Joule/s=1W
Explanation
The correct answer is 1 Joule/s=1W because the unit of power is defined as the rate at which work is done or energy is transferred. 1 Volt multiplied by 1 Ampere gives us 1 Watt, which is equivalent to 1 Joule per second.
25.
1Coulomb is subjected to 1V/m electric field
Correct Answer
B. 1 N force developed
Explanation
The given information states that 1 Coulomb is subjected to a 1V/m electric field. According to the formula F = qE, where F is the force, q is the charge, and E is the electric field strength, we can calculate the force developed. Since the charge is 1 Coulomb and the electric field strength is 1V/m, the force developed would be 1 N. Therefore, the correct answer is 1 N force developed.
26.
Q coulomb charge creates D(R) electric flux density
Correct Answer
B. Q/(4πR^2)
Explanation
The electric flux density created by a coulomb charge is given by Q/(4πR^2). This is because the electric flux density is inversely proportional to the square of the distance from the charge (R^2), and directly proportional to the magnitude of the charge (Q). The factor of 4π is included to account for the spherical nature of the electric field, as the flux density spreads out uniformly in all directions around the charge. Therefore, the correct answer is Q/(4πR^2).
27.
D electric flux density is equal to
Correct Answer
A. εE
Explanation
The electric flux density (D) is equal to the product of the permittivity of the material (ε) and the electric field intensity (E). This relationship is given by the equation D = εE.
28.
B magnetic flux density is equal to
Correct Answer
B. µH
Explanation
The correct answer is µH. In electromagnetism, magnetic flux density (B) is related to the magnetic field strength (H) by the permeability of the medium (µ). This relationship is given by B = µH. Therefore, the correct answer is µH as it represents the correct equation relating magnetic flux density to magnetic field strength.
29.
Velocity of Light 'c' in free space is equal to
Correct Answer
B. 1/√(µoε0)
Explanation
The correct answer is 1/√(µoε0). This is because the velocity of light in free space is determined by the properties of the medium through which it travels. In free space, the velocity of light is equal to 1/√(µoε0), where µo is the permeability of free space and ε0 is the permittivity of free space. These constants represent the ability of free space to transmit electric and magnetic fields, respectively. Therefore, the velocity of light in free space is dependent on the product of these two constants, which is equal to 1/√(µoε0).
30.
µo is
Correct Answer
B. Absolute permeability
Explanation
The correct answer is absolute permeability. Absolute permeability is a property of a material that measures its ability to allow magnetic flux to pass through it. It is represented by the symbol µo and is a constant value in a vacuum. It is used in calculations related to magnetic fields and electromagnetic waves.
31.
εo is
Correct Answer
A. Absolute permittivity
Explanation
The correct answer is absolute permittivity. Absolute permittivity, denoted by εo, is a fundamental constant in physics that represents the ability of a material to store electrical energy in an electric field. It is a measure of how easily an electric field can penetrate a material. The value of εo is approximately 8.854 x 10^-12 farads per meter (F/m) in a vacuum.
32.
Relative permittivity of air is
Correct Answer
D. 1
Explanation
The relative permittivity of air is 1. Relative permittivity, also known as dielectric constant, is a measure of a material's ability to store electrical energy in an electric field. Air has a relative permittivity of 1 because it has a very low ability to store electrical energy compared to other materials. This means that air is a poor electrical insulator and allows electric charges to move through it easily.
33.
Relative permeability of air is
Correct Answer
A. 1
Explanation
The relative permeability of air is 1. Relative permeability is a dimensionless quantity that describes how easily a material can be magnetized. The relative permeability of air is close to 1 because air is a non-magnetic material and does not exhibit any significant magnetic properties. This means that air does not enhance or inhibit the flow of magnetic fields and is considered to have negligible magnetic permeability.
34.
Value of µo is
Correct Answer
C. 4π×10^-7 H/m
Explanation
The value of µo is 4π×10^-7 H/m. This is because µo, also known as the permeability of free space, is a constant that represents the magnetic permeability of a vacuum. It is defined as the ratio of the magnetic field strength to the magnetic flux density. In the SI system, the value of µo is approximately equal to 4π×10^-7 H/m.
35.
Potential Drop
Correct Answer
A. Integral of E
Explanation
The correct answer is "Integral of E" because the integral of a function represents the area under the curve of that function. In this context, "E" likely represents an electric field, and taking the integral of the electric field would give the potential drop, which is a measure of the change in electric potential between two points.
36.
Electric Field is
Correct Answer
B. Negative potential grad.
Explanation
The correct answer is "negative potential grad." This is because the electric field is defined as the negative gradient of the electric potential. The electric potential represents the amount of electric potential energy per unit charge at a given point in space. The negative sign indicates that the electric field points in the direction of decreasing potential, which is from higher potential to lower potential.
37.
Newton×Meter
Correct Answer
A. Joule
Explanation
The correct answer is Joule because Joule is the SI unit of energy and work, which is equal to the work done by a one newton force acting over a one-meter distance. Newton-meter is another unit of energy, but it is equivalent to Joule, so it is not a separate option. Watt is the SI unit of power, which is the rate at which work is done or energy is transferred. The derivative of Watt is not a valid unit of measurement in this context.
38.
Kg×m/s^2
Correct Answer
B. Newton
Explanation
The given correct answer is "Newton." Newton is the unit of measurement for force in the International System of Units (SI). It is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. The unit is named after Sir Isaac Newton, who made significant contributions to the field of physics and formulated the laws of motion.
39.
Mgh
Correct Answer
B. Potential energy
Explanation
The equation "mgh" represents the potential energy of an object. "m" represents the mass of the object, "g" represents the acceleration due to gravity, and "h" represents the height of the object above a reference point. Potential energy is the energy possessed by an object due to its position or condition, and it can be converted into other forms of energy. In this case, the equation indicates that the object has potential energy based on its mass and height.
40.
(1/2)mv^2
Correct Answer
A. Kinetic energy
Explanation
The equation (1/2)mv^2 represents the formula for calculating kinetic energy. Kinetic energy is the energy possessed by an object due to its motion. The equation takes into account the mass (m) of the object and its velocity (v). The factor of 1/2 is included to account for the relationship between the object's mass and velocity. Therefore, the correct answer is kinetic energy.
41.
I (moment of inertia)×ω(radians/sec)
Correct Answer
C. J(angular momentum)
Explanation
Angular momentum (J) is the correct answer because it is the product of moment of inertia (I) and angular velocity (ω). Angular momentum is a vector quantity that represents the rotational motion of an object. It depends on the distribution of mass around an axis of rotation (moment of inertia) and how fast the object is rotating (angular velocity). The formula for angular momentum is J = Iω. Linear momentum (p) and energy are not directly related to the product of moment of inertia and angular velocity.
42.
(1/2)I×ω^2
Correct Answer
B. Rotational Kinetic Energy
Explanation
The given expression, I×ω^2, represents the rotational kinetic energy. This is because I represents the moment of inertia, which is a measure of an object's resistance to rotational motion, and ω represents the angular velocity, which is the rate at which an object rotates. When these two values are multiplied and squared, it gives the rotational kinetic energy of the object. Therefore, the correct answer is rotational kinetic energy.
43.
Torque×angle
Correct Answer
C. Rotational energy
Explanation
Rotational energy refers to the energy possessed by an object due to its rotation. It is dependent on both torque and angle, as torque is the force that causes rotational motion and angle represents the amount of rotation. Therefore, the product of torque and angle directly contributes to the amount of rotational energy an object possesses. The other options, such as watt (a unit of power), angular acceleration (rate of change of angular velocity), and none, are not directly related to rotational energy.
44.
Moment of Inertia×Angular Acceleration=
Correct Answer
B. Torque=Rotational Force
Explanation
The equation Moment of Inertia multiplied by Angular Acceleration equals Torque. Torque is the rotational force applied to an object, causing it to rotate around an axis. The Moment of Inertia represents an object's resistance to changes in its rotational motion. Angular Acceleration measures how quickly an object's angular velocity changes over time. Therefore, Torque is directly related to the Moment of Inertia and Angular Acceleration, making it the correct answer.
45.
Current × Resistance
Correct Answer
C. Voltage drop
Explanation
Voltage drop is the correct answer because it is the term used to describe the decrease in electric potential across a component or circuit element. When current flows through a resistor, for example, there is a drop in voltage due to the resistance encountered. This drop in voltage is essential for the proper functioning of electrical circuits and can be calculated using Ohm's law.
46.
What is the material in Cathode?
Correct Answer
C. Strontium Barium CuO
Explanation
The material in the cathode is Strontium Barium CuO. This is because the cathode is typically made of a material that can emit electrons when heated, and Strontium Barium CuO is known to have good electron emission properties. Tungsten is commonly used in cathodes, but it is not listed as an option. Copper and Aluminum are not suitable materials for cathodes as they do not have the necessary electron emission properties.
47.
What is the Work Function of StBaCuO?
Correct Answer
B. 1eV
Explanation
The work function of a material refers to the amount of energy required to remove an electron from the material's surface. In this case, the work function of StBaCuO is 1eV, which means that it takes 1 electron volt of energy to remove an electron from the surface of StBaCuO.
48.
At what temperature Thermionic Emission occurs
Correct Answer
B. 1000◦C
Explanation
Thermionic emission refers to the process of electrons being emitted from a heated surface. At higher temperatures, more electrons gain enough energy to overcome the work function of the material and escape into the surrounding space. The given answer of 1000◦C suggests that this is the temperature at which a significant number of electrons are emitted through thermionic emission. At temperatures below 1000◦C, the number of emitted electrons would be lower, while at temperatures above 1000◦C, the emission would be even more pronounced.
49.
What atomic model did Thomson propose?
Correct Answer
B. Plum-Pudding Model
Explanation
Thomson proposed the Plum-Pudding Model of the atom. In this model, the atom is compared to a plum pudding, with the positive charge spread uniformly throughout the atom and the negatively charged electrons embedded within it. This model suggested that the atom is composed of a positively charged substance with negatively charged electrons scattered within it, similar to the distribution of raisins in a plum pudding. However, later experiments led to the discovery of the nucleus and the development of new atomic models.
50.
When did Vacuum Tube Era start ?
Correct Answer
A. 1903
Explanation
The Vacuum Tube Era started in 1903. This era refers to the period when vacuum tubes were widely used in electronic devices such as radios, televisions, and early computers. Vacuum tubes were crucial components in these devices as they allowed for the amplification and control of electrical signals. The invention and development of vacuum tubes revolutionized the field of electronics and paved the way for the advancement of technology in the early 20th century.