List of top Physics Questions

If the length of a string is \(P\) when the tension in it is 6 N and its length is \(Q\) when the tension in it is 8 N, then the original length of the string is:

When a monochromatic light is incident on a surface separating two media, both the reflected and refracted lights have the same: 

A circular coil of area 200 cm\(^2\) and 50 turns is rotating about its vertical diameter with an angular speed of 40 rad/s in a uniform horizontal magnetic field of magnitude \(2 \times 10^{-2} \, \text{T}\). The maximum emf induced in the coil is.
If a bar magnet of moment \( 10^{-4} \) Am\(^2\) is kept in a uniform magnetic field of \( 12 \times 10^{-3} \) T such that it makes an angle of \( 30^\circ \) with the direction of the magnetic field, then the torque acting on the magnet is:

In Bohr model of hydrogen atom, if the difference between the radii of \( n^{th} \) and\( (n+1)^{th} \)orbits is equal to the radius of the \( (n-1)^{th} \) orbit, then the value of \( n \) is:

If the temperature of a gas is increased from \( 27^\circ C \) to \( 159^\circ C \), the increase in the rms speed of the gas molecules is:
Two positive point charges are separated by a distance of 4 m in air. If the sum of the two charges is \( 36 \mu C \) and the electrostatic force between them is \( 0.18 \) N, then the bigger charge is:
The self-induced emf of a coil is 36 V. If the current in the coil is changed from 12 A to 24 A in one second, then the change in the energy stored in the coil is:
Two photons of energies 2.5 eV and 5.5 eV incident on a metal surface of work function 1.5 eV. The ratio of the maximum speeds of the photoelectrons emitted from the metal surface is:
The relation between the current \( i \) (in ampere) in a conductor and the time \( t \) (in second) is given by \( i = 12t + 9t^2 \). The charge passing through the conductor between the times \( t = 2 \, \text{s} \) and \( t = 10 \, \text{s} \) is.
The difference between the fundamental frequencies of an open pipe and a closed pipe of the same length is 100 Hz. The difference between the frequencies of the second harmonic of the open pipe and the third harmonic of the closed pipe is:

Young's double slit experiment is performed with monochromatic light of wavelength \( 6000 \text{Ã…} \). If the intensity of light at a point on the screen where the path difference is \( 2000 \text{Ã…} \) is \( I_1 \) and the intensity of light at a point where path difference is \( 1000 \text{Ã…} \) is \( I_2 \), then the ratio \( I_1: I_2 \) is:

The most exotic diamagnetic materials are:
A current \( i \) flows through a circular loop of radius \( R \). The ratio of the magnetic field produced at its centre to the field produced at a point at a distance \( \frac{R}{\sqrt{3}} \) from its centre on its axis is:

Consider an isolated system of two concentric spherical black bodies. The inner sphere of radius \( R \) is at temperature \( T \), and the outer sphere of radius \( 4R \) is at temperature \( 2T \). The rate of absorption of radiant energy by the outer sphere is: 

The displacement of a particle in simple harmonic motion is given by: \[ x = A_0 \cos \left( \frac{\pi}{2} t \right) \] The distance traveled by the particle in the interval between \( t = 2 \) and \( t = 5 \) seconds and its position at \( t = 5 \) second are:
A solid sphere rolls down without slipping from the top of an inclined plane of height 28 m and angle of inclination 30°. The velocity of the sphere when it reaches the bottom of the plane is (Acceleration due to gravity \( g = 10 \, \text{m/s}^2 \))
A cell of emf 2 V is connected to an external resistor. If the current through the resistor is 200 mA and the terminal voltage of the cell is 87.5% of the emf of the cell, then the internal resistance of the cell is:
The maximum range of a projectile is 80 m. If the projectile is projected with the same speed at an angle of \( \frac{\pi}{12} \) with the horizontal, then the range of the projectile is:
The gas that gives the highest fractional conversion of heat to work in an isobaric process is:

An alphabet 'a' made of two similar thin uniform metal plates of each length \( L \) and width \( a \) is placed on a horizontal surface as shown in the figure. If the alphabet is vertically inverted, the shift in the position of its center of mass from the horizontal surface is:

Resonance phenomenon is exhibited by a circuit only if:
The refractive index of the material of a small angled prism is \( 1.6 \). If the angle of minimum deviation is \( 4.2^\circ \), the angle of the prism is?
After the decay of a single \( \beta^- \) particle, the parent and daughter nuclei are?
The escape speed of a body from the surface of the earth is 11.2 km/s. The escape speed of a body from the surface of a planet whose mass is 8 times that of the earth and mean density same as that of the earth is: