List of top Physics Questions

Two identical parallel plate air capacitors are connected in series to a battery of e.m.f. \( V \). If one of the capacitors is inserted in liquid of dielectric constant \( K \), then potential difference of the other capacitor will become

From a disc of mass \( M \) and radius \( R \), a circular hole of diameter \( R \) is cut whose rim passes through the centre. The moment of inertia of the remaining part of the disc about perpendicular axis passing through the centre is

A glass convex lens is of refractive index 1.55 with both faces of same radius of curvature. What will be the radius of curvature if focal length is to be 20 cm?

Due to surface tension, the excess pressure inside a smaller drop is 9 units. If 27 smaller drops combine, then the excess pressure inside the bigger drop is

The 3rd overtone of a closed organ pipe is in unison with 3rd overtone of an open pipe. The ratio of the length of the closed pipe to the length of open pipe is

An alternating e.m.f. is given by \( e = e_0 \sin \omega t \). In what time the e.m.f. will have half its maximum value, if \( e_0 \) starts from zero? (T = Time period)

The polarising angle for a transparent medium is \( \theta \) and \( v \) is the speed of light in that medium, then relation between \( \theta \) and \( v \) is (c = velocity of light)

What should be the velocity of earth due to rotation about its own axis so that the weight at equator becomes \( \frac{1}{25} \) of initial value?
(Radius of Earth on equator = 6400 km, \( g = 10 \, \text{m/s}^2 \), \( \cos 0^\circ = 1 \))

In energy band diagram of insulators, a band gap and the conduction band is respectively

The unknown resistances are connected in two gaps of a metre bridge. The null point is at 20 cm from zero end. A resistance of 15 \( \Omega \) is connected in series with the smaller of the two. The null point shifts to 40 cm. The smaller resistance is

When a photosensitive surface is irradiated by lights of wavelengths \( \lambda_1 \) and \( \lambda_2 \), kinetic energies of emitted photoelectrons are \( E_1 \) and \( E_2 \) respectively. The work function of the photosensitive surface is

If a gas is compressed isothermally then the r.m.s. velocity of the molecules

Light of incident frequency 2 times the threshold frequency is incident on a photosensitive material. If the incident frequency is made \( \frac{1}{3} \)rd and intensity is doubled then the photoelectric current will

A circular and a square coil is prepared from two identical metal wires and a current is passed through them. Ratio of magnetic dipole moment associated with circular coil to that with square coil is

Two galvanometers 'G1' and 'G2' require 2 mA and 3 mA respectively to produce the same deflection. Then

In communication system, for a given block diagram of receiver, the boxes 'X' and 'Y' respectively represent

The length of seconds pendulum is 1 m on the earth. If the mass and diameter of the planet is double that of the earth, then the length of the seconds pendulum on the planet will be

A body of mass 5 kg is moving in a straight line. The relation between its displacement and time is \( x = (t^3 - 2t - 10) \) m. What is the force acting on it at the end of 5 seconds?

A torque of 50 Nm acts on a body for 8 seconds which is initially at rest. The change in its angular momentum is

A steel wire of length \( L \) and area of cross-section \( A \) is suspended from rigid support. If \( Y \) is the Young's modulus of material of the wire and \( \alpha \) is the coefficient of linear expansion, then the increase in tension when temperature falls by \( t^\circ C \) is

The linear displacement \( x \) of the bob of simple pendulum from its mean position varies as \( x = a \sin \left( \frac{\pi}{2} t \right) \), where \( a \) is its amplitude expressed in meter and \( t \) is in second. The length of simple pendulum is (Take \( g = \pi^2 \, \text{m/s}^2 \))

Let \( \mu_1 \) and \( \mu_2 \) be the refractive indices of two media. \( v_1 \) and \( v_2 \) are the velocities of light in the media respectively. Which one of the following relations is TRUE?

The materials having negative magnetic susceptibility are

A wire of magnetic material of length \( 2L \) and magnetic moment \( M \) is bent at the centre to form 'L' shaped wire. Its magnetic moment is

A toroid has a non-ferromagnetic wire of inner radius \( r_1 \) and outer radius \( r_2 \), around which \( N \) turns of wire are wound. If the current in the wire is \( I \), then the magnetic field inside the toroid is