List of top Physics Questions

The magnetic moments associated with two closely wound circular coils a and b of radius \(r\) and \(2r\) respectively are equal if (where \(N_a\), \(I_a\) and \(N_b\), \(I_b\) are number of turns and current in A and B respectively)

In an experiment to find emf of a cell using potentiometer, the length of null point for a cell of emf \(1.5\) V is found to be \(60\) cm. If this cell is replaced by another cell of emf \(E\), the length of null point increases by \(40\) cm. The value of \(E\) is \(x/10\) V.
The value of \(x\) is

A charged particle \(q\) is accelerated by a potential difference of \(V\) enters a region of uniform magnetic field of induction \(B\) at right angles to the direction of the field. The charged particle completes semi circle of the radius \(r\) inside the magnetic field. The mass of the charged particle is (all quantities are in SI units)

A parallel plate capacitor with air between the plate has a capacitance of \(15\) pF. The separation between the plates becomes twice and the space between them is filled with a medium of dielectric constant \(3.5\). Then the capacitance becomes \(x/4\) pF.
The value of \(x\) is

A rod with a circular cross-section area \(2\) cm\(^2\) and length \(40\) cm is wound uniformly with \(400\) turns of an insulated wire. If a current \(0.4\) A flows in the wire winding, the total magnetic flux produced inside the winding is \(4π\times 10^{-6}\) Wb. The relative permeability of the rod is
(Given permeability of vacuum \(μ_0 = 4π\times 10^{-7}\) N m A\(^{-2}\))

Two long straight wires are arranged parallel to each other and are kept \(20\) cm apart in vacuum. They carry currents of \(2\) A and \(4\) A respectively in the same direction. What will be the magnetic force on a length of \(10\) cm of either wire?
(\(μ_0 = 4π\times 10^{-7}\) SI units)

If two charges \(q_1\) and \(q_2\) are separated with distance 'd' and placed in a medium of dielectric constant \(K\). What will be the equivalent distance between charges in air for the same electrostatic force?

Two isolated metallic spheres of radii \(R\) and \(2R\) are charged such that both have the same charge density \(σ\). The spheres are then connected by a thin conducting wire. If the new charge density of the larger sphere is \(σ_1\). The ratio \(σ_1\) to \(σ\) is

The distance between two consecutive points with phase difference of \(60^{\circ}\) in a wave of frequency \(n\) is \(x\) meter. The velocity with which wave is traveling is

A traveling wave is described by the equation \(y(x,t) = [0.05sin(8x-4t)]\) m
The velocity of the wave is [All the quantities are in SI unit]

The amplitude of a particle executing SHM is \(3\) cm. The displacement at which its kinetic energy will be \(25\%\) more than the potential energy is (in cm)

Two waves are represented by the equations, \(y_1 = asin(ωt+kx+0.57)\) m and \(y_2 = acos(ωt+kx)\) m, where \(x\) is in metre and \(t\) is in second. What is the phase difference between them? (\(π = 3.14\))

Sound waves travel at \(350\) m/s through a warm air and at \(3500\) m/s through brass. Which of the following is correct about the wavelength of a \(700\) Hz accoustic wave as it enters brass from warm air?

The velocity of a particle executing SHM varies with displacement (\(x\)) as \(4v^2 = 50-x^2\).
The time period of oscillations is \(x/7\) s.
The value of \(x\) is (Take \(π = 22/7\))

Let \(γ_1\) be the ratio of molar specific heat at constant pressure and molar specific heat at constant volume of a mono-atomic gas and \(γ_2\) be the similar ratio of diatomic gas. Considering the diatomic gas molecule as a rigid rotator, the ratio, \(γ_1/γ_2\) is

A block is fastened to a horizontal spring. The block is pulled to a distance \(x = 10\) cm from its equilibrium position (at \(x = 0\)) on a frictionless surface from rest. The kinetic energy of the block at \(x = 5\) cm is \(0.25\) J. The spring constant of the spring is nearly (in \(\text{Nm}^{-1}\))

According to law of equipartition of energy the molar specific heat of a non rigid diatomic gas at constant volume is

What will be the ratio of rate of radiation of metal sphere at two different temperatures \(T_1 = 527^{\circ}\)C and \(T_2 = 127^{\circ}\)C

Energy of a gas/litre is \(600\) joule, then what will be its pressure?

The coefficient of thermal conductivity of a metal rod depends on its

A sample of gas at temperature \(T\) is adiabatically expanded to double its volume. The work done by the gas in the process is (given, \(γ = \frac{3}{2}\)):

A spherical drop of liquid splits into \(1000\) identical spherical drops. If \(u_i\) is the surface energy of the original drop and \(u_f\) is the total surface energy of the resulting drops, the (ignoring evaporation). \(u_f/u_i = (10/x)\). Then value of \(x\) is

The surface of water in a water tank of cross-section area \(750\) cm\(^2\) on the top of a house is \(h\) m above the tap level. The speed of water coming out through the tap of cross-section area \(500\) mm\(^2\) is \(30\) cm/s. At that instant, \(dh/dt\) is \(y\times 10^{-3}\) m/s. The value of \(y\) will be

A solid sphere of mass \(1\) kg rolls without slipping on a plane surface. Its kinetic energy is \(7\times 10^{-3}\) J. The speed of the center of mass of the sphere in cm s\(^{-1}\) is

Determine the ratio of surface energy of \(1\) large drop to \(1\) small drop, if \(1000\) small drops combined to form \(1\) large drop.