List of top Physics Questions

The oxygen gas of 5 moles is heated at constant pressure from 300 K to 320 K. The amount of energy spent during this expansion is 
(For oxygen \( C_p = 7 \, {Cal/mol} \cdot \degree C \), \( C_v = 5 \, {Cal/mol} \cdot \degree C \)) 
 

In which of the following thermodynamic processes, the total amount of heat supplied to the system is only used to rise the temperature?
A substance of mass \( m \) requires a power input of \( P \) to remain in the molten state at its melting point. When the power is turned off, the sample completely solidifies in time \( t \). The latent heat of the substance is
A U-tube is partially filled with water. Oil which does not mix with water is next poured into one side of the U-tube until entire water rises by 25 cm on the other side. If the density of oil is 0.8 g cm\(^{-3}\), the oil level will stand higher than the water level by:
The Poisson’s ratio of a material is 0.4. If the force is applied to a wire of this material, there is a decrease of cross-sectional area by 2%. The percentage increase in its length is:
The gravitational field due to a mass distribution is \( E = \frac{K}{x^3} \) along x-direction (K is a constant). Taking the gravitational potential to be zero at infinity, its value at a distance \( x \) is:

The mass 'm' oscillates in simple harmonic motion with an amplitude 'A' as shown in the figure. 
The amplitude of point \(P\) is 

 


 

The displacement of a particle varies with time as \( x = 4 \sin 3\omega t \). If its motion is simple harmonic, then its maximum acceleration is:
A torque of 10 Nm is applied on a wheel having angular momentum of 2 kg m\(^2\) s\(^{-1}\). The angular momentum of the wheel after 4 s is:
A solid flywheel of mass 20 kg and radius 100 mm revolves at 600 revolutions per minute. If the coefficient of friction is 0.1 and to stop the flywheel in 3.14 s, the force to be applied against is approximately:
A ball strikes a horizontal floor at 45°. If 25% of its kinetic energy is lost in the collision, then the coefficient of restitution is:
An elevator can carry a maximum load of 2000 kg (elevator + passengers) and is moving up with a constant speed of 9 km/h. If the frictional force opposing the motion is \( 5 \times 10^3 \) N, the minimum power delivered by the motor to the elevator is (acceleration due to gravity = 10 ms\(^2\))
A body slides down an inclined plane of angle of inclination 30\(^\circ\) with a constant velocity of 10 ms\(^{-1}\). If the body is pushed up the same plane with a velocity of 20 ms\(^{-1}\), the distance moved by the body before coming to rest is (acceleration due to gravity = 10 ms\(^2\))
The apparent weight of a girl in a moving lift is 25% more than her true weight. If the lift starts from rest, the distance travelled by the girl in the first 2 s is (acceleration due to gravity = 10 ms\(^2\))
A body is projected horizontally from the top of a tall tower. At a time of 3.5 s from the projection, the horizontal and vertical displacements of the body are equal. The velocity of projection of the body is (acceleration due to gravity = 10 ms\(^2\))
The velocity of a boat in still water is 13 ms\(^{-1}\). If water in a river is flowing with a velocity of 5 ms\(^{-1}\), the ratio of the times taken by the boat to cross the river in the shortest path and shortest time is

The relation between velocity \( V \) (in ms\(^{-1}\)) and the displacement \( x \) (in meters) of a particle in motion is \( 2V = \sqrt{37 + 32x} \). 
The acceleration of the particle is 
 

If the errors in the measurement of the mass and side of a cubical block are 2% and 1% respectively, then the error in the determination of the density of the material of the block is
A particle connected with light thread is performing vertical circular motion. Speed at point B (Lowermost point) is sufficient, so that it is able to complete its circular motion. Ignoring air friction, find the ratio of kinetic energy at A to that at B. (A being top-most point)
A particle connected with light thread is performing vertical circular motion

Wave picture of light has failed to explain
(1) photoelectric effect
(2) interference of light
(3) diffraction of light
(4) polarization of light

 A capacitor of capacitance (4.0 ± 0.2) μF is charged to a potential of (10.0 ± 0.1) V. The charge on the capacitor is:

A body is thrown vertically upwards with a velocity of 35 ms−1 from the ground.The ratio of the speeds of the body at times 3 s and 4 s of its motion is:

From a height of  'h' above the ground, a ball is projected up at an angle \( 30^\circ \) with the horizontal. If the ball strikes the ground with a speed of 1.25 times its initial speed of \( 40 \ ms^{-1} \), the value of 'h' is:

A block is kept on a rough horizontal surface. The acceleration of the block increases from \( 6 \ ms^{-2} \) to \( 11 \ ms^{-2} \) when the horizontal force acting on it increases from \( 20 \ N \) to \( 30 \ N \). The coefficient of kinetic friction between the block and the surface is: (Acceleration due to gravitiy = 10ms-^2)

The kinetic energy of a body of mass 4 kg moving with a velocity of (2î − 4ĵ − k̂) m/s is?