List of top Physics Questions

A helicopter has metallic blades with length 4 m extending outward from the central point and rotating at 3 rev/s. If the vertical component of Earth's magnetic field is 40 ÂµT, then the emf induced between the blade tip and the central point is

A superconductor exhibits:

Two bar magnets A and B are identical and arranged as shown. Their lengths are negligible compared to the separation between them. A magnetic needle placed between the magnets at point P gets deflected through an angle \( \theta \) under their influence. The ratio of distances \( d_1 \) and \( d_2 \) is:

Two charged particles of the same charge but different masses \(m_1\) and \(m_2\) are projected with the same velocity \(V\) normally into the uniform magnetic field \(B\) as shown in the figure. The maximum separation of the particles is:

A wire of resistance 0.2 \( \Omega/{cm} \) is bent to form a square ABCD of side 10 cm. A similar wire is connected between the corners B and D. If 2 V battery is connected across A and C, the power dissipated is

What is the equivalent resistance between the points A and B of the network?

“Introduction of a small charged sphere into a larger one allows us to keep piling up a larger and larger amount of charge on the latter” – This is the principle of the:

A parallel plate capacitor has two plates of area 'A' separated by distance 'd'. The capacitor is charged to a potential difference 'V' and the battery is disconnected. A metal plate with area 'A' and thickness \( \frac{d}{2} \) is inserted between the plates, so that it is always parallel to the plates. The work done on the metal slab while it was inserted is:

A rectangular coil of size 15 cm \( \times \) 20 cm is placed in XY plane in a region of uniform electric field \( 3 \times 10^3 \, {KVm}^{-1} \). Then the electric flux through the coil is:

The ratio of kinetic energy of a molecule of neon to that of the oxygen gas at 27Â°C is

A gas with a ratio of specific heats, \( \gamma = \frac{4}{3} \), is heated isobarically. The percentage of the given heat used in external work done is

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:

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 45Â°. 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\(^2\))