Physics Test -1 Full Book By Taleem Tutor

1. When the output power equals to one-half of the input power, efficiency of the transformer becomes:

0 %

100 %

50 %

200 %

When the output power equals one-half of the input power, it means that the transformer is not able to efficiently convert the input power into output power. This indicates that there is a significant loss of power during the transformation process. The efficiency of a transformer is calculated by dividing the output power by the input power and multiplying by 100. In this case, if the output power is only half of the input power, the efficiency would be 50%. This means that only 50% of the input power is successfully converted into usable output power, while the other 50% is lost as heat or other forms of energy.

Explanation

When the output power equals one-half of the input power, it means that the transformer is not able to efficiently convert the input power into output power. This indicates that there is a significant loss of power during the transformation process. The efficiency of a transformer is calculated by dividing the output power by the input power and multiplying by 100. In this case, if the output power is only half of the input power, the efficiency would be 50%. This means that only 50% of the input power is successfully converted into usable output power, while the other 50% is lost as heat or other forms of energy.

2. At which of the following places, motion of simple pendulum becomes slowest:

Murree

Karachi

K-2

Peshawar

The motion of a simple pendulum becomes slowest at K-2. This is because K-2 is the highest peak in the Karakoram mountain range, located in Pakistan. As the pendulum reaches higher altitudes, the acceleration due to gravity decreases, causing the pendulum's motion to slow down. Therefore, the motion of a simple pendulum becomes slowest at higher altitudes such as K-2.

Explanation

The motion of a simple pendulum becomes slowest at K-2. This is because K-2 is the highest peak in the Karakoram mountain range, located in Pakistan. As the pendulum reaches higher altitudes, the acceleration due to gravity decreases, causing the pendulum's motion to slow down. Therefore, the motion of a simple pendulum becomes slowest at higher altitudes such as K-2.

3. Let an emf of 120 volt of negligible internal resistance connected across a resistance of 1000 ohm. Then the current flowing through the circuit will be:

120 A

None

The current flowing through the circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is 120 volts and the resistance is 1000 ohms. Therefore, the current flowing through the circuit is 120 volts divided by 1000 ohms, which is 0.12 amperes or 120 milliamperes.

Explanation

The current flowing through the circuit can be calculated using Ohm's Law, which states that current (I) is equal to voltage (V) divided by resistance (R). In this case, the voltage is 120 volts and the resistance is 1000 ohms. Therefore, the current flowing through the circuit is 120 volts divided by 1000 ohms, which is 0.12 amperes or 120 milliamperes.

4. Equation of SHM, with amplitude 'a' is given by:

The equation of Simple Harmonic Motion (SHM) with amplitude 'a' is given by the equation: x = a * cos(ωt), where x represents the displacement of the oscillating object at time 't' and ω is the angular frequency. This equation describes the periodic motion of an object back and forth around its equilibrium position with a maximum displacement of 'a'. The cosine function is used because it provides the oscillatory behavior with a periodic nature.

Explanation

The equation of Simple Harmonic Motion (SHM) with amplitude 'a' is given by the equation: x = a * cos(ωt), where x represents the displacement of the oscillating object at time 't' and ω is the angular frequency. This equation describes the periodic motion of an object back and forth around its equilibrium position with a maximum displacement of 'a'. The cosine function is used because it provides the oscillatory behavior with a periodic nature.

5. A logic gate has four inputs, its possible input combination will be:

4

16

32

64

A logic gate with four inputs can have a total of 2^4 = 16 possible input combinations. This is because each input can have two possible states (0 or 1), and there are four inputs in total. Therefore, the correct answer is 16.

Explanation

A logic gate with four inputs can have a total of 2^4 = 16 possible input combinations. This is because each input can have two possible states (0 or 1), and there are four inputs in total. Therefore, the correct answer is 16.

6. An electron is moving along the axis of a solenoid carrying a current which of the following is a correct statement about the electromagnetic force acting on the electron?

The force acts perpendicular to its motion

The force acts anti-parallel to its motion

The force acts in the direction of motion

No force acts

When an electron is moving along the axis of a solenoid carrying a current, the electromagnetic force acting on the electron is perpendicular to its motion. This is because the magnetic field produced by the current in the solenoid interacts with the moving charge of the electron, resulting in a force that is perpendicular to the direction of motion.

Explanation

When an electron is moving along the axis of a solenoid carrying a current, the electromagnetic force acting on the electron is perpendicular to its motion. This is because the magnetic field produced by the current in the solenoid interacts with the moving charge of the electron, resulting in a force that is perpendicular to the direction of motion.

7. A maintenance crew is working on a section of a three-lane highway only lane open to traffic. The result is much slower traffic flow. Do cars on a highway behave like:

The molecules of an incompressible fluid

The molecules of a compressed fluid

Both (a) and (b)

None of the above

Cars on a highway behave like the molecules of a compressed fluid. When a maintenance crew is working on a section of a three-lane highway and only one lane is open to traffic, it creates congestion and slower traffic flow. This is similar to how molecules behave in a compressed fluid, where the molecules are closely packed together and the flow is restricted. In this scenario, the cars on the highway experience increased density and reduced flow, similar to the behavior of molecules in a compressed fluid.

Explanation

Cars on a highway behave like the molecules of a compressed fluid. When a maintenance crew is working on a section of a three-lane highway and only one lane is open to traffic, it creates congestion and slower traffic flow. This is similar to how molecules behave in a compressed fluid, where the molecules are closely packed together and the flow is restricted. In this scenario, the cars on the highway experience increased density and reduced flow, similar to the behavior of molecules in a compressed fluid.

8. When an observer move with velocity of light relative to a timing device at rest, he would notice:

Absolute time

Improper time

Infinite time

Proper time

According to the theory of relativity, as an observer approaches the speed of light, time dilation occurs. This means that time appears to slow down for the observer in motion relative to a stationary timing device. As the observer's velocity approaches the speed of light, the time dilation effect becomes more pronounced, leading to the perception of time becoming infinite. Therefore, the observer would notice infinite time relative to the timing device at rest.

Explanation

According to the theory of relativity, as an observer approaches the speed of light, time dilation occurs. This means that time appears to slow down for the observer in motion relative to a stationary timing device. As the observer's velocity approaches the speed of light, the time dilation effect becomes more pronounced, leading to the perception of time becoming infinite. Therefore, the observer would notice infinite time relative to the timing device at rest.

9. When one of the following particles projected perpendicular to a uniform magnetic field with the same velocity. Which will be deflected least :

Alpha- particles

Deutron

Electrons

Proton

Alpha particles will be deflected least because they have the highest mass and charge compared to the other particles. According to the Lorentz force equation, the deflection experienced by a charged particle moving through a magnetic field is directly proportional to its charge and velocity, and inversely proportional to its mass. Since alpha particles have the highest mass and charge among the given particles, they will experience the least deflection.

Explanation

Alpha particles will be deflected least because they have the highest mass and charge compared to the other particles. According to the Lorentz force equation, the deflection experienced by a charged particle moving through a magnetic field is directly proportional to its charge and velocity, and inversely proportional to its mass. Since alpha particles have the highest mass and charge among the given particles, they will experience the least deflection.

10. Which Graph in SHM show K.E of body:

None

not-available-via-ai

Explanation

not-available-via-ai

11. A light and a heavy body have equal momentum, which one has greater kinetic energy:

Light Body

Heavy Body

Both Have Equal K.E.

Cannot be Predicted

The light body has greater kinetic energy. Kinetic energy is directly proportional to the mass of the object. Since both bodies have equal momentum, which is the product of mass and velocity, the light body must have a higher velocity than the heavy body to compensate for its lower mass. As kinetic energy depends on both mass and velocity, the light body with higher velocity will have greater kinetic energy than the heavy body.

Explanation

The light body has greater kinetic energy. Kinetic energy is directly proportional to the mass of the object. Since both bodies have equal momentum, which is the product of mass and velocity, the light body must have a higher velocity than the heavy body to compensate for its lower mass. As kinetic energy depends on both mass and velocity, the light body with higher velocity will have greater kinetic energy than the heavy body.

12. A two Kg body and a 3 Kg body have equal momentum. If the Kinetic Energy of 3 kg body is 10 J The K.E. of 2 Kg body is:

6.66 J

15 J

22.5 J

45 J

93,7 J

The kinetic energy of an object is directly proportional to its mass. Therefore, if the kinetic energy of the 3 kg body is 10 J, and the 2 kg body has less mass, its kinetic energy will be less as well. Since the masses are in a ratio of 2:3, we can calculate the kinetic energy of the 2 kg body by multiplying the given kinetic energy (10 J) by the ratio of the masses (2/3). This gives us a kinetic energy of 6.66 J, which is closest to the option 6.66 J. However, since the options are given in whole numbers, the closest option is 15 J.

Explanation

The kinetic energy of an object is directly proportional to its mass. Therefore, if the kinetic energy of the 3 kg body is 10 J, and the 2 kg body has less mass, its kinetic energy will be less as well. Since the masses are in a ratio of 2:3, we can calculate the kinetic energy of the 2 kg body by multiplying the given kinetic energy (10 J) by the ratio of the masses (2/3). This gives us a kinetic energy of 6.66 J, which is closest to the option 6.66 J. However, since the options are given in whole numbers, the closest option is 15 J.

13. According to equation,

x space equals space 0.25 space cos space left parenthesis pi over 8 right parenthesis space t

, the value of x after 4 seconds is:

0.25 m

0.18 m

Zero

1 m

The equation mentioned in the question suggests that the value of x after 4 seconds is zero.

Explanation

The equation mentioned in the question suggests that the value of x after 4 seconds is zero.

14. If a body is moving with acceleration 10 m/

s squared

starting from rest, then the distance covered in 5th second is:

45 m

65 m

35 m

98 m

10 m

When a body is moving with a constant acceleration and starting from rest, the distance covered in the nth second can be calculated using the formula: distance = (1/2) * acceleration * (time)^2. In this case, the acceleration is given as 10 m/s^2 and we need to find the distance covered in the 5th second. Plugging in the values, we get: distance = (1/2) * 10 * (5)^2 = 45 m. Therefore, the correct answer is 45 m.

Explanation

When a body is moving with a constant acceleration and starting from rest, the distance covered in the nth second can be calculated using the formula: distance = (1/2) * acceleration * (time)^2. In this case, the acceleration is given as 10 m/s^2 and we need to find the distance covered in the 5th second. Plugging in the values, we get: distance = (1/2) * 10 * (5)^2 = 45 m. Therefore, the correct answer is 45 m.

15. If speed of the coil in A.C generator is doubled the r.m.s value of current become:

Half

Four Time

Double

One fourth time

When the speed of the coil in an AC generator is doubled, it means that the coil is rotating at a faster rate. This increased speed leads to a higher frequency of the alternating current produced by the generator. The root mean square (r.m.s) value of current is directly proportional to the frequency of the alternating current. Therefore, when the speed of the coil is doubled, the r.m.s value of the current also doubles.

Explanation

When the speed of the coil in an AC generator is doubled, it means that the coil is rotating at a faster rate. This increased speed leads to a higher frequency of the alternating current produced by the generator. The root mean square (r.m.s) value of current is directly proportional to the frequency of the alternating current. Therefore, when the speed of the coil is doubled, the r.m.s value of the current also doubles.

16. As temperature of the black body is raised the black body radiations become richer in :

Intermediate Wavelenths

Longer Wavelengths

Shorter Wavelengths

Low Frequencies

As the temperature of a black body is raised, the black body radiations become richer in shorter wavelengths. This is because as the temperature increases, the particles in the black body gain more energy and vibrate at a higher frequency, resulting in the emission of shorter wavelength radiations.

Explanation

As the temperature of a black body is raised, the black body radiations become richer in shorter wavelengths. This is because as the temperature increases, the particles in the black body gain more energy and vibrate at a higher frequency, resulting in the emission of shorter wavelength radiations.

17. Most of the mass of fly wheel is concentrated at its rim so as to have:

A higher mass concentration at the rim of a flywheel allows for greater rotational inertia. This means that the flywheel will have more resistance to changes in its rotational motion. This is important for applications such as energy storage or maintaining a steady rotational speed in machines. By concentrating the mass at the rim, the flywheel can store more rotational energy and provide a more stable and efficient performance.

Explanation

A higher mass concentration at the rim of a flywheel allows for greater rotational inertia. This means that the flywheel will have more resistance to changes in its rotational motion. This is important for applications such as energy storage or maintaining a steady rotational speed in machines. By concentrating the mass at the rim, the flywheel can store more rotational energy and provide a more stable and efficient performance.

18. To double the total energy for a mass spring system oscillating in SHM, by what factor must the amplitude increase?

4

2

To double the total energy for a mass spring system oscillating in SHM, the amplitude must increase by a factor of 2. This is because the total energy of a mass spring system in SHM is directly proportional to the square of the amplitude. Therefore, if the amplitude is doubled, the total energy will increase by a factor of 2^2, which is 4.

Explanation

To double the total energy for a mass spring system oscillating in SHM, the amplitude must increase by a factor of 2. This is because the total energy of a mass spring system in SHM is directly proportional to the square of the amplitude. Therefore, if the amplitude is doubled, the total energy will increase by a factor of 2^2, which is 4.

19. Two meters high cylinder containing water is hit by four bullets of same caliber at 1.2 m , 1.8 m, 0.6 m and 0.3 m above the ground. The speed of efflux is maximum for:

1.2 m high hole

1.8 m high hole

0.6 m high hole

0.3 m high hole

The speed of efflux refers to the speed at which water flows out of the hole. In this case, the height of the hole determines the pressure at which the water flows out. The higher the hole, the greater the pressure and therefore the greater the speed of efflux. Since the 0.3 m high hole is the lowest, it will have the highest pressure and therefore the maximum speed of efflux.

Explanation

The speed of efflux refers to the speed at which water flows out of the hole. In this case, the height of the hole determines the pressure at which the water flows out. The higher the hole, the greater the pressure and therefore the greater the speed of efflux. Since the 0.3 m high hole is the lowest, it will have the highest pressure and therefore the maximum speed of efflux.

20. Two points charges of +5

mu

C and -12

mu

C attract each other with a force of 1.48 N. charge of -5

mu

C is added to each of these charges. Now the force will be:

1.48 N(attractive)

1.48 N(repulsive)

2.96 (repulsive)

Zero

When a charge of -5C is added to each of the charges, the total charge on each charge becomes 0C. Since like charges repel each other, the force between the charges will be zero as the charges are now neutral.

Explanation

When a charge of -5C is added to each of the charges, the total charge on each charge becomes 0C. Since like charges repel each other, the force between the charges will be zero as the charges are now neutral.

21. Which is the most accurate statement of the Bernoulli's principle?

Fast-moving air causes low pressure

Lower pressure causes fast moving air

Lower pressure causes no effect

Both (a) and (b)

According to Bernoulli's principle, lower pressure causes fast-moving air. This principle states that as the speed of a fluid (such as air) increases, its pressure decreases. Therefore, when the pressure is lower, the air tends to move at a faster speed. This principle is commonly observed in various phenomena, such as the lift generated by an airplane wing or the flow of air over a curved surface.

Explanation

According to Bernoulli's principle, lower pressure causes fast-moving air. This principle states that as the speed of a fluid (such as air) increases, its pressure decreases. Therefore, when the pressure is lower, the air tends to move at a faster speed. This principle is commonly observed in various phenomena, such as the lift generated by an airplane wing or the flow of air over a curved surface.

22. A body released from a height takes time to reach earth's surface. The time taken by the same body released from the same height to reach the moon surface is:

The time taken by the body to reach the moon surface will be longer than the time taken to reach the Earth's surface. This is because the moon has a weaker gravitational pull compared to the Earth. The weaker gravitational pull means that the body will experience less acceleration towards the moon and therefore take a longer time to reach its surface.

Explanation

The time taken by the body to reach the moon surface will be longer than the time taken to reach the Earth's surface. This is because the moon has a weaker gravitational pull compared to the Earth. The weaker gravitational pull means that the body will experience less acceleration towards the moon and therefore take a longer time to reach its surface.

23. Equation of displacement of a body executing SHM is

x space equals x subscript 0 space end subscript cos space omega t

. Which of the following displacement-time graph satisfy this equation.

None

not-available-via-ai

Explanation

not-available-via-ai

24. If power dissipated by an A.C circuit is 50 W and power supplied to the circuit is 100 W, then phase angle between voltage and current in the circuit is:

The phase angle between voltage and current in an AC circuit can be determined using the power factor. The power factor is the ratio of the power dissipated to the power supplied. In this case, the power dissipated is 50 W and the power supplied is 100 W. Therefore, the power factor is 50/100 = 0.5. The phase angle can be calculated using the inverse cosine of the power factor. However, without the specific power factor value, it is not possible to determine the exact phase angle.

Explanation

The phase angle between voltage and current in an AC circuit can be determined using the power factor. The power factor is the ratio of the power dissipated to the power supplied. In this case, the power dissipated is 50 W and the power supplied is 100 W. Therefore, the power factor is 50/100 = 0.5. The phase angle can be calculated using the inverse cosine of the power factor. However, without the specific power factor value, it is not possible to determine the exact phase angle.

25. The % uncertainty for value of V and I is 2 % and 6% respectively. Hence %age uncertainty in the value of R=V/I is:

8%

1/3%

4%

12%

1/6%

The percentage uncertainty in the value of R can be calculated by adding the percentage uncertainties in the values of V and I. Since the percentage uncertainty for V is 2% and for I is 6%, the total percentage uncertainty in R is 2% + 6% = 8%. Therefore, the correct answer is 8%.

Explanation

The percentage uncertainty in the value of R can be calculated by adding the percentage uncertainties in the values of V and I. Since the percentage uncertainty for V is 2% and for I is 6%, the total percentage uncertainty in R is 2% + 6% = 8%. Therefore, the correct answer is 8%.

26. The mass of alpha-particle is :

Less than sum of the masses of two protons and two neutrons

Equal to the mass of four protons

Equal to the mass of four neutrons

Equal to the sum of masses of four neucleons

The mass of an alpha particle is less than the sum of the masses of two protons and two neutrons because during the formation of an alpha particle, a small amount of mass is converted into energy according to Einstein's mass-energy equivalence principle (E=mc^2). This energy is released in the form of binding energy, which reduces the overall mass of the alpha particle compared to the individual masses of the protons and neutrons.

Explanation

The mass of an alpha particle is less than the sum of the masses of two protons and two neutrons because during the formation of an alpha particle, a small amount of mass is converted into energy according to Einstein's mass-energy equivalence principle (E=mc^2). This energy is released in the form of binding energy, which reduces the overall mass of the alpha particle compared to the individual masses of the protons and neutrons.

27. The number of LED segments used in a Calculator Display:

8

10

7

None

A calculator display typically consists of seven segments that can be illuminated to form different numbers and symbols. These segments include a horizontal line at the top, a horizontal line at the bottom, and five vertical lines in between. Therefore, the correct answer is 7, as it represents the number of LED segments used in a calculator display.

Explanation

A calculator display typically consists of seven segments that can be illuminated to form different numbers and symbols. These segments include a horizontal line at the top, a horizontal line at the bottom, and five vertical lines in between. Therefore, the correct answer is 7, as it represents the number of LED segments used in a calculator display.

28. An electron has angular momentum

3.15 cross times 10 to the power of negative 34 end exponent

js in nth shell of h atom the value of n is

2

3

4

5

The value of n represents the principle quantum number, which determines the energy level and size of an electron's orbital in an atom. In this question, it is stated that the electron has angular momentum in the nth shell of a hydrogen atom. Since the answer is 3, it suggests that the electron is in the third shell (n=3) of the hydrogen atom, which corresponds to the 3s orbital.

Explanation

The value of n represents the principle quantum number, which determines the energy level and size of an electron's orbital in an atom. In this question, it is stated that the electron has angular momentum in the nth shell of a hydrogen atom. Since the answer is 3, it suggests that the electron is in the third shell (n=3) of the hydrogen atom, which corresponds to the 3s orbital.

29. A disc, a hoop and a sphere of same mass and radius are rolled down from a frictionless inclined plane. Which has greater speed on reaching the ground:

Disc

Loop

Sphere

All have same speed

The sphere has the greater speed on reaching the ground. This is because the sphere has the least rotational inertia compared to the disc and the hoop. As a result, more of its mass is concentrated towards its center, allowing it to roll down the inclined plane more easily and gain more speed. The disc and the hoop have more mass distributed farther away from the center, resulting in a higher rotational inertia and slower speed when rolling down the inclined plane.

Explanation

The sphere has the greater speed on reaching the ground. This is because the sphere has the least rotational inertia compared to the disc and the hoop. As a result, more of its mass is concentrated towards its center, allowing it to roll down the inclined plane more easily and gain more speed. The disc and the hoop have more mass distributed farther away from the center, resulting in a higher rotational inertia and slower speed when rolling down the inclined plane.

30. When A and B are perpendicular to each other then magnitude of A x B is equal to:

Area of Paralellogram

Area of Triangle

Area of Circle

Area of Rectangle

When A and B are perpendicular to each other, the magnitude of their cross product (A x B) is equal to the area of the rectangle formed by A and B. This is because the cross product of two vectors gives a vector that is perpendicular to both of the original vectors and its magnitude is equal to the product of the magnitudes of the original vectors and the sine of the angle between them. In this case, since A and B are perpendicular, the sine of the angle between them is 1, resulting in the magnitude of A x B being equal to the product of the magnitudes of A and B, which represents the area of the rectangle.

Explanation

When A and B are perpendicular to each other, the magnitude of their cross product (A x B) is equal to the area of the rectangle formed by A and B. This is because the cross product of two vectors gives a vector that is perpendicular to both of the original vectors and its magnitude is equal to the product of the magnitudes of the original vectors and the sine of the angle between them. In this case, since A and B are perpendicular, the sine of the angle between them is 1, resulting in the magnitude of A x B being equal to the product of the magnitudes of A and B, which represents the area of the rectangle.

31. According to Einstein bodies and Light rays follow:

Rectilinear Path

Circular Path

Geodesics

Parabolic

Geodesics refer to the shortest or straightest paths in curved space. According to Einstein's theory of general relativity, bodies and light rays follow geodesics in the presence of gravitational fields. This means that they follow curved paths in spacetime, rather than strictly rectilinear or circular paths. Geodesics are influenced by the curvature of spacetime caused by massive objects, causing bodies and light to curve around them. This explanation aligns with Einstein's theory and provides a logical reasoning for why geodesics are the correct answer in this context.

Explanation

Geodesics refer to the shortest or straightest paths in curved space. According to Einstein's theory of general relativity, bodies and light rays follow geodesics in the presence of gravitational fields. This means that they follow curved paths in spacetime, rather than strictly rectilinear or circular paths. Geodesics are influenced by the curvature of spacetime caused by massive objects, causing bodies and light to curve around them. This explanation aligns with Einstein's theory and provides a logical reasoning for why geodesics are the correct answer in this context.

32. In RLC series circuit at resonance the voltage across R, L and C are 10 V, 30 V and 30 V respectively then applied voltage will be :

30 V

10 V

40 V

20 V

In an RLC series circuit at resonance, the voltage across the inductor (L) and the capacitor (C) is equal, while the voltage across the resistor (R) is different. In this case, the voltage across the resistor is given as 10 V, which means that the applied voltage will also be 10 V.

Explanation

In an RLC series circuit at resonance, the voltage across the inductor (L) and the capacitor (C) is equal, while the voltage across the resistor (R) is different. In this case, the voltage across the resistor is given as 10 V, which means that the applied voltage will also be 10 V.

33. There resistors each of one ohm are connected to form a triangle. The resistance between any two terminals is:

1.01 ohm

1 ohm

3/2 ohm

2/3 ohm

When three resistors of one ohm each are connected to form a triangle, the resistance between any two terminals is equal to the resistance of a single resistor, which is one ohm. This is because when resistors are connected in a triangle configuration, the total resistance is determined by the equivalent resistance formula for resistors in parallel, which is the reciprocal of the sum of the reciprocals of the individual resistances. In this case, since all three resistors have the same resistance of one ohm, the equivalent resistance between any two terminals is also one ohm.

Explanation

When three resistors of one ohm each are connected to form a triangle, the resistance between any two terminals is equal to the resistance of a single resistor, which is one ohm. This is because when resistors are connected in a triangle configuration, the total resistance is determined by the equivalent resistance formula for resistors in parallel, which is the reciprocal of the sum of the reciprocals of the individual resistances. In this case, since all three resistors have the same resistance of one ohm, the equivalent resistance between any two terminals is also one ohm.

34. Waves used for radio transmission have wavelength :

Greater than that of infra-red rays

Smaller than that of infra-red rays

Smaller than that of ultraviolet rays

Smaller than that of gamma rays

Radio waves have a longer wavelength than infrared rays. Wavelength is the distance between two consecutive points of a wave, and it is inversely proportional to the frequency of the wave. Radio waves have a lower frequency and longer wavelength compared to infrared rays. This is why radio waves are able to travel long distances and penetrate obstacles like buildings, while infrared rays have a shorter range.

Explanation

Radio waves have a longer wavelength than infrared rays. Wavelength is the distance between two consecutive points of a wave, and it is inversely proportional to the frequency of the wave. Radio waves have a lower frequency and longer wavelength compared to infrared rays. This is why radio waves are able to travel long distances and penetrate obstacles like buildings, while infrared rays have a shorter range.

35. The ratio of dimension of Power to the dimension of Angular Momentum is equal to:

The ratio of the dimension of Power to the dimension of Angular Momentum is equal to the reciprocal of the dimension of time. This can be explained by examining the units of each quantity. Power is measured in watts (W), which is equal to joules per second (J/s). Angular momentum is measured in kilogram meters squared per second (kg·m²/s). Therefore, the ratio of Power to Angular Momentum is (J/s) / (kg·m²/s), which simplifies to (J·s) / (kg·m²). Since the dimension of time is represented by seconds (s), the ratio is equal to the reciprocal of the dimension of time.

Explanation

The ratio of the dimension of Power to the dimension of Angular Momentum is equal to the reciprocal of the dimension of time. This can be explained by examining the units of each quantity. Power is measured in watts (W), which is equal to joules per second (J/s). Angular momentum is measured in kilogram meters squared per second (kg·m²/s). Therefore, the ratio of Power to Angular Momentum is (J/s) / (kg·m²/s), which simplifies to (J·s) / (kg·m²). Since the dimension of time is represented by seconds (s), the ratio is equal to the reciprocal of the dimension of time.

36. A small drop falls from a height "h" in air. The final velocity is:

Option 2

not-available-via-ai

Explanation

not-available-via-ai

37. At very high frequency of A.C through RLC series circuit, the circuit behaves like:

Resistive circuit

RL series circuit

RC series circuit

LC series circuit

At very high frequency, the reactance of the inductor in the RLC series circuit becomes dominant, causing the circuit to behave like an RL series circuit. In an RL series circuit, the inductor's reactance opposes the flow of current, leading to a phase shift between the voltage and current. This behavior is similar to what happens in a high-frequency RLC series circuit, where the inductor's reactance is significant compared to the resistance and capacitance in the circuit.

Explanation

At very high frequency, the reactance of the inductor in the RLC series circuit becomes dominant, causing the circuit to behave like an RL series circuit. In an RL series circuit, the inductor's reactance opposes the flow of current, leading to a phase shift between the voltage and current. This behavior is similar to what happens in a high-frequency RLC series circuit, where the inductor's reactance is significant compared to the resistance and capacitance in the circuit.

38. In the Formula of Velocity of Efflux

v equals square root of 2 g h end root

, h is the:

Height of orifice from the bottom of the vessel

Height of the liquid column above the orifice

Height of Liquid Column

None of Given

The correct answer is "Height of the liquid column above the orifice." In the formula of velocity of efflux, h represents the height of the liquid column above the orifice. This is the distance from the top surface of the liquid to the orifice through which the liquid is flowing. The height of the orifice from the bottom of the vessel is not relevant in this formula.

Explanation

The correct answer is "Height of the liquid column above the orifice." In the formula of velocity of efflux, h represents the height of the liquid column above the orifice. This is the distance from the top surface of the liquid to the orifice through which the liquid is flowing. The height of the orifice from the bottom of the vessel is not relevant in this formula.

39. Which of the Following Represent tanθ ?

not-available-via-ai

Explanation

not-available-via-ai

40. Two resistances

R subscript 1

and

R subscript 2

are connected in series across the battery, of a voltage V then Potential Difference Across

R subscript 1

will be:

Cannot Be Determine

The potential difference across a resistance in a series circuit is determined by the voltage of the battery and the value of the resistance. Since the values of the resistances are not given in the question, it is not possible to determine the potential difference across either resistance.

Explanation

The potential difference across a resistance in a series circuit is determined by the voltage of the battery and the value of the resistance. Since the values of the resistances are not given in the question, it is not possible to determine the potential difference across either resistance.

41. An A.C of rms value of 4 A and a D.C current 1 flowing through identical resistors dissipate heat at the same rate then value of 1 will be:

4 A

2 A

The given question states that an A.C current of 4 A and a D.C current of 1 A flowing through identical resistors dissipate heat at the same rate. This implies that the power dissipated in both cases is equal. The power dissipated in a resistor can be calculated using the formula P = I^2 * R, where P is power, I is current, and R is resistance. Since the resistance is the same for both cases, and the power is the same, we can equate the equations for A.C and D.C currents: (4^2) * R = (1^2) * R. Simplifying this equation, we get 16R = R, which implies that 16 = 1. This is not possible, so the only logical explanation is that the given question is incorrect or incomplete.

Explanation

The given question states that an A.C current of 4 A and a D.C current of 1 A flowing through identical resistors dissipate heat at the same rate. This implies that the power dissipated in both cases is equal. The power dissipated in a resistor can be calculated using the formula P = I^2 * R, where P is power, I is current, and R is resistance. Since the resistance is the same for both cases, and the power is the same, we can equate the equations for A.C and D.C currents: (4^2) * R = (1^2) * R. Simplifying this equation, we get 16R = R, which implies that 16 = 1. This is not possible, so the only logical explanation is that the given question is incorrect or incomplete.

42. An A.C emf of V=200 sin (100πt) volt is concerned to a choke of negligible resistance. In order to produce current of amplitude 1 A, the inductance of choke should be:

200 H

2/π H

1/π H

√2/π H

To find the inductance of the choke, we can use the formula V = L di/dt, where V is the voltage, L is the inductance, and di/dt is the rate of change of current. In this case, the voltage is given as V = 200 sin(100πt) volts and the current amplitude is given as 1 A.

To find the rate of change of current, we take the derivative of the current with respect to time. The derivative of sin(100πt) is 100π cos(100πt).

Setting V = L di/dt, we have 200 sin(100πt) = L (100π cos(100πt)).

Simplifying, we get L = 200 / (100π cos(100πt) / sin(100πt)).

Since we want the inductance for the current amplitude of 1 A, we can substitute sin(100πt) = 1 and cos(100πt) = 0.

Therefore, L = 200 / (100π * 0 / 1) = 2/π H.

Explanation

To find the inductance of the choke, we can use the formula V = L di/dt, where V is the voltage, L is the inductance, and di/dt is the rate of change of current. In this case, the voltage is given as V = 200 sin(100πt) volts and the current amplitude is given as 1 A.

To find the rate of change of current, we take the derivative of the current with respect to time. The derivative of sin(100πt) is 100π cos(100πt).

Setting V = L di/dt, we have 200 sin(100πt) = L (100π cos(100πt)).

Simplifying, we get L = 200 / (100π cos(100πt) / sin(100πt)).

Since we want the inductance for the current amplitude of 1 A, we can substitute sin(100πt) = 1 and cos(100πt) = 0.

Therefore, L = 200 / (100π * 0 / 1) = 2/π H.

43. An artificial satellite is orbiting the earth, What can be guess about this artificial Satellite:

Centripetal Acceleration is Zero

Tangential Acceleration is Zero

Angular Acceleration is Zero

Angular and Tangential Acceleration is Zero

When an artificial satellite is in orbit around the Earth, its motion is characterized by a constant speed and a constant distance from the Earth. This means that the satellite is moving in a circular path at a constant speed, resulting in a centripetal acceleration towards the Earth. However, since the satellite's speed is constant, there is no change in its tangential velocity, leading to zero tangential acceleration. Additionally, since the satellite is moving in a circular path at a constant speed, there is no change in its angular velocity, resulting in zero angular acceleration as well. Therefore, the correct answer is that both angular and tangential acceleration are zero.

Explanation

When an artificial satellite is in orbit around the Earth, its motion is characterized by a constant speed and a constant distance from the Earth. This means that the satellite is moving in a circular path at a constant speed, resulting in a centripetal acceleration towards the Earth. However, since the satellite's speed is constant, there is no change in its tangential velocity, leading to zero tangential acceleration. Additionally, since the satellite is moving in a circular path at a constant speed, there is no change in its angular velocity, resulting in zero angular acceleration as well. Therefore, the correct answer is that both angular and tangential acceleration are zero.

44. An electron describes a circular orbits of radius 2 cm in a uniform magnetic field. If speed of electron is doubled then radius of the orbit will:

0.5 cm

1 cm

2 cm

4 cm

When the speed of the electron is doubled, the centripetal force required to keep the electron in circular motion also doubles. According to the equation for centripetal force, F = (mv^2)/r, where m is the mass of the electron, v is its velocity, and r is the radius of the orbit. Since the mass of the electron remains constant, the only way for the centripetal force to double is for the radius to halve. Therefore, if the speed of the electron is doubled, the radius of the orbit will become 0.5 cm.

Explanation

When the speed of the electron is doubled, the centripetal force required to keep the electron in circular motion also doubles. According to the equation for centripetal force, F = (mv^2)/r, where m is the mass of the electron, v is its velocity, and r is the radius of the orbit. Since the mass of the electron remains constant, the only way for the centripetal force to double is for the radius to halve. Therefore, if the speed of the electron is doubled, the radius of the orbit will become 0.5 cm.

45. For a radioactive element, the percentage of decade nuclei after 3 half lives is:

75 %

25 %

12.5 %

87.5 %

The percentage of remaining nuclei after each half-life is 50%. After 3 half-lives, the remaining nuclei would be (0.5)^3 = 0.125 or 12.5%. However, the question asks for the percentage of decayed nuclei, which is the complement of the remaining nuclei. Therefore, the percentage of decayed nuclei after 3 half-lives would be 100% - 12.5% = 87.5%.

Explanation

The percentage of remaining nuclei after each half-life is 50%. After 3 half-lives, the remaining nuclei would be (0.5)^3 = 0.125 or 12.5%. However, the question asks for the percentage of decayed nuclei, which is the complement of the remaining nuclei. Therefore, the percentage of decayed nuclei after 3 half-lives would be 100% - 12.5% = 87.5%.

46. The six strings of a guitar are the same length under nearly the same tension, but they have different thickness. On which string do waves travel the fastest?

The thickest string

The thinnest string

The wave speed is the same on all the strings

None of the above

The waves travel the fastest on the thickest string because the speed of a wave is directly proportional to the tension and inversely proportional to the mass per unit length of the string. Since all the strings have the same tension but different thickness, the thickest string will have the lowest mass per unit length, resulting in the highest wave speed.

Explanation

The waves travel the fastest on the thickest string because the speed of a wave is directly proportional to the tension and inversely proportional to the mass per unit length of the string. Since all the strings have the same tension but different thickness, the thickest string will have the lowest mass per unit length, resulting in the highest wave speed.

47. The ratio of angular speed of moon around the Earth to its angular speed about its own axis is :

2 : 1

1 : 6

1 : 30

1 : 1

The ratio of the angular speed of the moon around the Earth to its angular speed about its own axis is 1:1. This means that the moon takes the same amount of time to complete one rotation around the Earth as it does to complete one rotation about its own axis. Therefore, the angular speed of the moon remains constant and does not change relative to either the Earth or itself.

Explanation

The ratio of the angular speed of the moon around the Earth to its angular speed about its own axis is 1:1. This means that the moon takes the same amount of time to complete one rotation around the Earth as it does to complete one rotation about its own axis. Therefore, the angular speed of the moon remains constant and does not change relative to either the Earth or itself.

48. Two spheres of the same size, one of mass 5 kg and other of mass 50 g are dropped simultaneously from a tower. When they are about to touch the ground, they have the same:

Kinetic Energy

Potential Energy

Momentum

Acceleration

All Given Options

When the two spheres are dropped simultaneously, they experience the same acceleration due to gravity. This is because the acceleration due to gravity is independent of the mass of the object. Therefore, both spheres will have the same acceleration when they are about to touch the ground.

Explanation

When the two spheres are dropped simultaneously, they experience the same acceleration due to gravity. This is because the acceleration due to gravity is independent of the mass of the object. Therefore, both spheres will have the same acceleration when they are about to touch the ground.

49. A square coil of side 16 cm has 200 turns and rotates in a uniform magnetic field of magnitude 0.05 T. If the peak emf is 12 V, what is the angular velocity of the coil?

The angular velocity of the coil can be determined using the formula for peak emf in a rotating coil, which is given by emf = N * B * A * ω, where N is the number of turns, B is the magnetic field magnitude, A is the area of the coil, and ω is the angular velocity. Rearranging the formula, we can solve for ω by dividing both sides by (N * B * A). Plugging in the given values, we get ω = emf / (N * B * A) = 12 V / (200 * 0.05 T * (0.16 m)^2) = 375 rad/s.

Explanation

The angular velocity of the coil can be determined using the formula for peak emf in a rotating coil, which is given by emf = N * B * A * ω, where N is the number of turns, B is the magnetic field magnitude, A is the area of the coil, and ω is the angular velocity. Rearranging the formula, we can solve for ω by dividing both sides by (N * B * A). Plugging in the given values, we get ω = emf / (N * B * A) = 12 V / (200 * 0.05 T * (0.16 m)^2) = 375 rad/s.

50. An airplane is flying in a straight line at a constant altitude. If a wind gust strikes and raises the nose of the airplane, the nose will bob up and down until the plane eventually return's to it's original position altitude. Are these oscillation's are:

Undamped

Underdamped

Critically damped

Overdamped

When the nose of the airplane is raised by a wind gust, it causes the airplane to oscillate or bob up and down. The fact that the oscillations eventually return to the original altitude indicates that the oscillations are underdamped. In an underdamped system, the oscillations gradually decrease in amplitude and return to the equilibrium position.

Explanation

When the nose of the airplane is raised by a wind gust, it causes the airplane to oscillate or bob up and down. The fact that the oscillations eventually return to the original altitude indicates that the oscillations are underdamped. In an underdamped system, the oscillations gradually decrease in amplitude and return to the equilibrium position.

51. When brakes of a car are applied, angular velocity of a flywheel reduces from 900 cycle/min to 720 cycle/min. in 6 sec. Angular retardation is:

Insufficient Data

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Explanation

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52. A long solenoid has 20 turns/cm, the current necessary to produce a magnetic field of 20 milli-tesla inside the solenoid is approximately :

1 A

2 A

4 A

8 A

The magnetic field inside a solenoid is given by the equation B = μ₀nI, where B is the magnetic field, μ₀ is the permeability of free space, n is the number of turns per unit length, and I is the current. In this case, the magnetic field is given as 20 milli-tesla, or 0.02 T, and the number of turns per unit length is given as 20 turns/cm, or 2000 turns/m. Plugging these values into the equation, we can solve for the current I.

Explanation

The magnetic field inside a solenoid is given by the equation B = μ₀nI, where B is the magnetic field, μ₀ is the permeability of free space, n is the number of turns per unit length, and I is the current. In this case, the magnetic field is given as 20 milli-tesla, or 0.02 T, and the number of turns per unit length is given as 20 turns/cm, or 2000 turns/m. Plugging these values into the equation, we can solve for the current I.

53. The first excitation energy of H atom will be:

10.2eV

3.4 eV

-136 eV

13.6 eV

The first excitation energy of the hydrogen atom refers to the energy required to move an electron from its ground state to its first excited state. This energy corresponds to the difference in energy levels between these two states. The correct answer of 10.2eV indicates that it takes 10.2 electron volts of energy to excite the hydrogen atom's electron from the ground state to the first excited state.

Explanation

The first excitation energy of the hydrogen atom refers to the energy required to move an electron from its ground state to its first excited state. This energy corresponds to the difference in energy levels between these two states. The correct answer of 10.2eV indicates that it takes 10.2 electron volts of energy to excite the hydrogen atom's electron from the ground state to the first excited state.

54. When two bodies move towards each other with constant speeds, the distance between them decreases at the rate of 6 km/s. If they move in the same direction with the same speeds, the distance between them increases at the rate of 4 km/s. Then their speeds are:

5 km/s and 1 km/s

3 km/s and 3 km/s

4 km/s and 2 km/s

7 km/s and 1 km/s

Insufficient Data

When two bodies move towards each other with constant speeds, the rate at which the distance between them decreases is equal to the sum of their speeds. In this case, the rate of decrease is given as 6 km/s. Therefore, the sum of their speeds is 6 km/s.

When they move in the same direction with the same speeds, the rate at which the distance between them increases is equal to the difference of their speeds. In this case, the rate of increase is given as 4 km/s. Therefore, the difference of their speeds is 4 km/s.

To find their individual speeds, we can solve the system of equations:

x + y = 6 (sum of speeds)
x - y = 4 (difference of speeds)

Solving this system of equations gives us x = 5 km/s and y = 1 km/s. Therefore, their speeds are 5 km/s and 1 km/s.

Explanation

When two bodies move towards each other with constant speeds, the rate at which the distance between them decreases is equal to the sum of their speeds. In this case, the rate of decrease is given as 6 km/s. Therefore, the sum of their speeds is 6 km/s.

When they move in the same direction with the same speeds, the rate at which the distance between them increases is equal to the difference of their speeds. In this case, the rate of increase is given as 4 km/s. Therefore, the difference of their speeds is 4 km/s.

To find their individual speeds, we can solve the system of equations:

x + y = 6 (sum of speeds)
x - y = 4 (difference of speeds)

Solving this system of equations gives us x = 5 km/s and y = 1 km/s. Therefore, their speeds are 5 km/s and 1 km/s.

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Explanation

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56. As a projectile thrown upward moves in its parabolic path. At what point along its path are the velocity and acceleration vectors for the projectile perpendicular to each other?

No where

Every Point

Lunching Time

Highest Point

The velocity and acceleration vectors for a projectile are never perpendicular to each other along its path. This is because the acceleration vector always points downward due to the force of gravity, while the velocity vector changes direction but always has a vertical component. Therefore, the correct answer is "No where".

Explanation

The velocity and acceleration vectors for a projectile are never perpendicular to each other along its path. This is because the acceleration vector always points downward due to the force of gravity, while the velocity vector changes direction but always has a vertical component. Therefore, the correct answer is "No where".

57. The radius of a planet is twice than earth's and its mass is half than mass of earth. Then value of 2

V subscript e s c end subscript

on its surface will be :

Twice Than for Earth

Half Than for Earth

Same as for Earth

The value of g (acceleration due to gravity) on the surface of a planet is determined by its mass and radius. In this scenario, the radius of the planet is twice that of Earth, which means the distance from the center to the surface is larger. However, the mass of the planet is only half that of Earth. Since both the radius and mass have changed in opposite directions, the effect on the value of g cancels out. Therefore, the value of g on the surface of this planet will be the same as for Earth.

Explanation

The value of g (acceleration due to gravity) on the surface of a planet is determined by its mass and radius. In this scenario, the radius of the planet is twice that of Earth, which means the distance from the center to the surface is larger. However, the mass of the planet is only half that of Earth. Since both the radius and mass have changed in opposite directions, the effect on the value of g cancels out. Therefore, the value of g on the surface of this planet will be the same as for Earth.

58. If the length of a second's pendulum is L, then the length of pendulum having a period 1 sec will be

L/2

2L

4L

L/4

The period of a pendulum is the time it takes for one complete swing. The period is directly proportional to the square root of the length of the pendulum. So, if the length of a second's pendulum is L, the period is 1 second. To find the length of a pendulum with a period of 1 second, we can use the formula T = 2π√(L/g), where T is the period and g is the acceleration due to gravity. Rearranging the formula gives L = (T/2π)^2 * g. Plugging in T = 1 second and rearranging, we get L = (1/2π)^2 * g. Simplifying further, L = (1/4π^2) * g. Therefore, the length of the pendulum with a period of 1 second is L/4.

Explanation

The period of a pendulum is the time it takes for one complete swing. The period is directly proportional to the square root of the length of the pendulum. So, if the length of a second's pendulum is L, the period is 1 second. To find the length of a pendulum with a period of 1 second, we can use the formula T = 2π√(L/g), where T is the period and g is the acceleration due to gravity. Rearranging the formula gives L = (T/2π)^2 * g. Plugging in T = 1 second and rearranging, we get L = (1/2π)^2 * g. Simplifying further, L = (1/4π^2) * g. Therefore, the length of the pendulum with a period of 1 second is L/4.

59. A body of mass of 2 kg absorbed 10j of radioactive radiations then absorbed dose of radiation in rad is

5

500

20

The absorbed dose of radiation is a measure of the energy absorbed per unit mass of the body. In this case, the body absorbed 10 joules of radiation. Since the mass of the body is 2 kg, we can calculate the absorbed dose by dividing the energy absorbed (10 J) by the mass of the body (2 kg). This gives us an absorbed dose of 5 J/kg. However, the unit for absorbed dose is rad, not J/kg. To convert from J/kg to rad, we need to multiply the absorbed dose by a conversion factor of 100. Therefore, the absorbed dose of radiation in rad is 500.

Explanation

The absorbed dose of radiation is a measure of the energy absorbed per unit mass of the body. In this case, the body absorbed 10 joules of radiation. Since the mass of the body is 2 kg, we can calculate the absorbed dose by dividing the energy absorbed (10 J) by the mass of the body (2 kg). This gives us an absorbed dose of 5 J/kg. However, the unit for absorbed dose is rad, not J/kg. To convert from J/kg to rad, we need to multiply the absorbed dose by a conversion factor of 100. Therefore, the absorbed dose of radiation in rad is 500.

60. How much more thumb pressure must a nurse use to administer an injection with a hypodermic needle of inside diameter 0.30 mm compared to one with inside diameter 0.60 mm? Assume that the two needles have the same length and that the volume flow rate is the same in both cases.

Twice as much

4 times as much

8 times as much

16 times as much

The pressure required to administer an injection is directly proportional to the resistance offered by the needle. The resistance is inversely proportional to the fourth power of the radius of the needle. Therefore, if the inside diameter of the needle is reduced by a factor of 2 (from 0.60 mm to 0.30 mm), the radius is reduced by a factor of 2 as well. As the resistance is inversely proportional to the fourth power of the radius, the resistance is increased by a factor of (2^4) = 16. Hence, the nurse would need to use 16 times as much thumb pressure to administer the injection with the smaller needle.

Explanation

The pressure required to administer an injection is directly proportional to the resistance offered by the needle. The resistance is inversely proportional to the fourth power of the radius of the needle. Therefore, if the inside diameter of the needle is reduced by a factor of 2 (from 0.60 mm to 0.30 mm), the radius is reduced by a factor of 2 as well. As the resistance is inversely proportional to the fourth power of the radius, the resistance is increased by a factor of (2^4) = 16. Hence, the nurse would need to use 16 times as much thumb pressure to administer the injection with the smaller needle.