List of top Physics Questions

The surface of a metal is illuminated with the light of 400 nm. The kinetic energy of the ejected photoelectrons was found to be 1.68 eV. The work function of the metal is: (hc = 1240 eV·nm)
A solid cylinder of mass \( m \) and radius \( R \) rolls down an inclined plane without slipping. The speed of its C.M. when it reaches the bottom is:
A and B are two wires. The radius of A is twice that of B. They are stretched by the same load. Then the stress on B is:
A planet revolves in an elliptical orbit around the sun. The semi-major and semi-minor axes are \( a \) and \( b \). Then the square of the time period, \( T \), is directly proportional to:
A block of mass 5 kg resting on a horizontal surface is connected by a cord, passing over a light frictionless pulley to a hanging block of mass 5 kg. The coefficient of kinetic friction between the block and the surface is 0.5. Tension in the cord is:
For a series RLC circuit \( R = X_L = 2X_C \). The impedance of the circuit and phase difference between \( V \) and \( I \) respectively will be:
Escape velocity when a body of mass \( m \) is thrown vertically from the surface of the earth is \( v \). What will be the escape velocity of another body of mass 4m thrown vertically?
A man holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally in 5 sec. Each bullet has a mass 10 g with a muzzle velocity of 800 m/s. The velocity which the rifle man attains after firing 10 shots will be:
In an electromagnetic wave:
A metal ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet is:
A particle having a mass 0.5 kg is projected under gravity with a speed of 98 m/s at an angle of \( 60^\circ \). The magnitude of the change in momentum (in N-sec) of the particle after 10 seconds is:
A particle covers half of the circle of radius \( r \). Then the displacement and distance of the particle are respectively:
The figure below shows currents in a part of electric circuit. The current \( i \) is:
Consider a pair of insulating blocks with thermal resistances \( R_1 \) and \( R_2 \) as shown in the figure. The temperature \( \theta \) at the boundary between the two blocks is:
A rain drop of radius 0.3 mm has a terminal velocity in air is 1 m/s. The viscosity of air is \( 8 \times 10^{-5} \) poise. The viscous force on it is:
A solid sphere is rotating in free space. If the radius of the sphere is increased keeping the mass the same, which one of the following will not be affected?
A mass of 0.5 kg moving with a speed of 1.5 m/s on a horizontal smooth surface, collides with a nearly weightless spring of force constant \( k = 50 \, \text{N/m} \). The maximum compression of the spring would be:
The Young’s modulus of a perfectly rigid body is:
The half-life period and the mean life period of a radioactive element are denoted respectively by \( T_h \) and \( T_m \). Then:
The equivalent capacitance of the combination of the capacitors is:
An electric dipole is kept in a uniform electric field. It experiences:
In a common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. The value of the base current amplification factor \( \beta \) will be:
The velocity-time graph of a body moving in a straight line is shown in the figure. Find the displacement and distance travelled by the body in 10 seconds.
A person swims in a river aiming to reach exactly on the opposite point on the bank of a river. His speed of swimming is 0.5 m/s at an angle of 120° with the direction of flow of water. The speed of water is:
The magnetic field at a distance \( r \) from a long wire carrying current is 0.4 tesla. The magnetic field at a distance \( 2r \) is: