List of top Physics Questions

A metal wire with circular cross section and length one metre is pulled with tensile force of 1000 N on each side. For the wire to be stretched not more than 0.25 cm, the minimum diameter of the wire required is:
(Young's modulus of the metal $= 10^{11}$ \text{ Pa, take } $\sqrt{\pi} = 1.77$)
A cylindrical rod made of aluminum has length 1 meter and diameter of 10 cm. The rod is subjected to a tensile force of 100 kN. The elongation in the rod is:
The particles with the following speed pass undeflected in the region of crossed fields
A drilling machine of power \(1~\text{kW}\) is used for 5 minutes to drill a hole in a \(10~\text{kg}\) metal block. If 40% of the work done by the machine is wasted as heat, the rise in temperature of the metal block is nearly (specific heat capacity of the metal = \(420~\text{J\,kg}^{-1}\text{K}^{-1}\))
An electron, a proton and an alpha particle are moving with same kinetic energy. If $ \lambda_1, \lambda_2, \lambda_3 $ are the de Broglie wavelengths of the electron, proton and alpha particle respectively, then
For a wavelength 670 nm of light coming from a galaxy moving with velocity $V$, the observed wavelength is 670.7 nm. The value of $V$ is
The electric field of an electromagnetic wave propagating in vacuum is given by $E = 35 \cos(kx - 4.5 \times 10^8 t)$ where $E_x$ and $t$ are in V/m and s respectively. The magnitude of the propagation vector $k$ is
The angular momentum of a solid cylinder rotating about its geometric axis with angular speed 40 rad s\(^{-1} \) is 2 kg m\(^2 \) s\(^{-1} \). If the radius of the cylinder is 10 cm, the mass of the cylinder is
A spherical ball of volume 2000 cm\(^3\) is subjected to a hydraulic pressure of 15 atm. If the change in volume is \( 5 \times 10^{-2} \) cm\(^3\), the bulk modulus of the material of the spherical ball is:
The number of rotational degrees of freedom of a diatomic molecule is
The shiny metal disk in the electric power meter (analog type) rotates due to:
The radius of the path of a charged particle of mass \( m \) and charge \( q \) moving with a speed \( v \) in a magnetic field \( B \) is given by:
The sum of the magnitudes of two vectors acting at a point is 18 and the magnitude of their resultant is 12. If the resultant is at \( 90^\circ \) with the vector of smaller magnitude, then the magnitudes of the vectors are

In the circuit given below, the charge on the capacitor $ C_1 $ is

The time period of a simple pendulum on the surface of the Earth is \( T \). At what height above the surface will the time period become \( 2T \)?
(Radius of Earth = \( 6400 \, \text{km} \))
A large open top water tank is completely filled with water. A small hole of diameter 4 mm is made 10 m below the water level. The flow rate of water through the hole is:
A wire is first bent in the form of a circular coil of 5 turns and the same wire is then bent in the form of another circular coil of 10 turns. If same current is passed in both the coils, then the ratio of the magnetic fields at their centres is
The specific heat capacity of a copper block of mass \( M \) is \( s \). If the mass of the copper block is doubled, the specific heat capacity will be:
In a medium in which a transverse progressive wave is travelling, the phase difference between two points with a separation of 1.25 cm is $ \frac{\pi}{4} $. If the frequency of the wave is 1000 Hz, the wave velocity will be
The change in internal energy when a gas is taken through a cyclic process completely once is
Beats are produced by frequencies \( \nu_1 \) and \( \nu_2 \) (\( \nu_1>\nu_2 \)). The duration of time between two successive minima is
A cyclotron’s oscillator frequency is 20 MHz. The operating magnetic field for accelerating protons is
(Charge of proton = \( 1.6 \times 10^{-19} \) C, mass of proton = \( 1.67 \times 10^{-27} \) kg)
An object of mass 50 kg is in a lift moving up with an acceleration of 5 ms$^{-2}$. Then the apparent weight of the object and its direction is (Acceleration due to gravity = 10 ms$^{-2}$)
In Young’s double slit experiment, if the distance between the two slits is decreased by 20% and the distance between the slits and the screen is increased by 20%, then the percentage increase in the fringe width is
If a body has a potential energy of \( (4x^2 + 2x) \, \text{J} \) at height 2 m, then the force acting on it is: