List of top Physics Questions

A source supplies heat to a system at the rate of \( 1000 W \). If the system performs work at the rate of \( 200 W \), the rate at which internal energy of the system increases is:
Truth table for the given circuit is:
Truth table for the given circuit is:
If \( R_C \) and \( R_B \) are respectively the resistances of in collector and base sides of the circuit, and \( \beta \) is the current amplification factor, then the voltage gain of a transistor amplifier in common emitter configuration is:
In the circuit shown in the figure, neglecting the source resistance, the voltmeter and ammeter readings respectively are:
voltmeter and ammeter readings
Light of wavelength \( 4000\text{\AA} \) is incident on a sodium surface for which the threshold wavelength of photoelectrons is \( 5420\text{\AA} \). The work function of sodium is:
The radiation of energy \( E \) falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
Resistance of a wire is \( 8\Omega \). It is drawn in such a way that it experiences a longitudinal strain of \( 400% \). The final resistance of the wire is:
Current flows in a conductor from east to west. The direction of the magnetic field at a point below the conductor is towards:
The magnitude of an electric field which can just suspend a deuteron of mass \( 3.2 \times 10^{-27} \) kg freely in air is:
Two charges \(5\) nC and \(-2\) nC are placed at points \( (5,0,0) \) and \( (23,0,0) \) in a region of space where there is no other external field. The electrostatic potential energy of this charge system is:
The space between the plates of a parallel plate capacitor is halved and a dielectric medium of relative permittivity \( 10 \) is introduced between the plates. The ratio of the final and initial capacitances of the capacitor is:
The angle between the axes of a polariser and an analyser is \( 45^\circ \). If the intensity of the unpolarized light incident on the polariser is \( I \), then the intensity of the light emerged from the analyser is:
The fundamental frequency of an open pipe is 100 Hz. If the bottom end of the pipe is closed and \( \frac{1}{3} \) of the pipe is filled with water, then the fundamental frequency of the pipe is:
The efficiency of a Carnot heat engine is 25% and the temperature of its source is 127°C. Without changing the temperature of the source, if the absolute temperature of the sink is decreased by 10%, the efficiency of the engine is:
The total internal energy of 2 moles of a monoatomic gas at a temperature 27°C is \( U \). The total internal energy of 3 moles of a diatomic gas at a temperature 127°C is:
The displacement of a particle of mass \(2g\) executing simple harmonic motion is \[ x = 8 \cos \left( 50t + \frac{\pi}{12} \right) \text{ m}, \] where \(t\) is time in seconds. The maximum kinetic energy of the particle is:
Two cylindrical vessels A and B of different areas of cross-section kept on the same horizontal plane are filled with water to the same height. If the volume of water in vessel A is 3 times the volume of water in vessel B, then the ratio of the pressures at the bottom of the vessels A and B is:
A ring and a disc of same mass and same diameter are rolling without slipping. Their linear velocities are same, then the ratio of their kinetic energy is:
A body of mass \( 30 \) kg moving with a velocity \( 20 \) ms\(^{-1}\) undergoes one-dimensional elastic collision with another ball of the same mass moving in the opposite direction with a velocity of \( 30 \) ms\(^{-1}\). After collision, the velocities of the first and second bodies respectively are:
A force of \( (4\hat{i} + 2\hat{j} + \hat{k}) \) N is acting on a particle of mass \( 2 \) kg displaces the particle from a position of \( (2\hat{i} + 2\hat{j} + \hat{k}) \) m to a position of \( (4\hat{i} + 3\hat{j} + 2\hat{k}) \) m. The work done by the force on the particle in joules is:
The acceleration of a body sliding down the inclined plane, having coefficient of friction \( \mu \), is
A body of 2 kg mass slides down with an acceleration of \( 4 \, \text{ms}^{-2} \) on an inclined plane having a slope of \( 30^\circ \). The external force required to take the same body up the plane with the same acceleration will be (Acceleration due to gravity \( g = 10 \, \text{ms}^{-2} \))
In the equation \( \left( P + \frac{a}{V^2} \right) (V - b) = RT \), where \( P \) is pressure, \( V \) is volume, \( T \) is temperature, \( R \) is the universal gas constant, and \( a, b \) are constants. The dimensions of \( a \) are:
The surface areas of two nuclei are in the ratio \( 9:25 \). The mass numbers of the nuclei are in the ratio:
A transmitter of power 10 kW emits radio waves of wavelength 500 m. The number of photons emitted per second by the transmitter is of the order of: