List of top Physics Questions

The magnetic potential energy stored in a certain inductor is \(49 \text{mJ}\) when the current in the inductor is \(70 \text{mA}\). The inductance of the inductor is

Two coils have a mutual inductance of \(0.005 \text{H}\). The current changes in the first coil according to equation \(I = I_0sinωt\), where \(I_0 = 10 \text{A}\) and \(ω = 60π \text{rad s}^{-1}\). The maximum values of e.m.f. in the second coil in volt will be

The region inside a current carrying toroid is filled with a material (Niobium) having susceptibility \(χ = 2.6\times 10^{-5}\). The percentage increase in the magnetic field in the presence of Niobium over that without it, is

In the circuit shown, when the current '\(i\)' is \(3\text{A}\) and increasing at the rate of \(1\text{A/s}\) the measurement of the potential difference between A and B is \(12 \text{V}\). But when the same current \(3\text{A}\) is decreasing at the rate of \(1\text{A/s}\), the measured potential difference \(V_{AB}\) between A and B is \(6\text{V}\). The value of 'R' in the circuit is

The ratio of magnetic field at the centre of the current carrying circular loop and its magnetic moment is '\(x\)'. When both the current and radius are tripled, then the ratio will be

In the following figure, the magnitude of the magnetic field at point 'O' will be

By connecting a resistance of \(980 \Omega\) in series with a galvanometer, it is converted into a voltmeter of a certain range. When the resistance of \(470 \Omega\) is connected in series, the range is halved. The resistance of the galvanometer is

In an oscillating LC circuit, the maximum charge on the capacitor is Q. When the energy is stored equally between the electric and magnetic fields, the charge on the capacitor becomes

A capacitor of capacitance C has charge Q and energy stored in it is W. If the charge is increased to 3Q, the energy stored in the capacitor W' will be

Two circular plates each of radius '\(r\)' are kept parallel to each other distance '\(d\)' apart. The capacitance of the capacitor formed is '\(C_1\)'. If the radius of each of the plates is increased to \(\sqrt{3}\) times the earlier radius and their distance of separation decreased to half the initial value, the capacitance now becomes '\(C_2\)'. The ratio \(C_1:C_2\) is

The point charges \(+q\), \(-q\), \(-q\), \(+q\), \(+Q\) and \(-q\) are placed at the vertices of a regular hexagon ABCDEF as shown in the figure.

The electric field at the centre of the hexagon 'O' due to the five charges at A, B, C, D and F is thrice the electric field at centre 'O' due to charge \(+Q\) at E alone. The value of Q is

A potentiometer wire of length \(4 \text{m}\) and resistance \(5 \Omega\) is connected in series with a resistance of \(992 \Omega\) and a cell of e.m.f. \(4 \text{V}\) with internal resistance \(3 \Omega\). The length of \(0.75 \text{m}\) on potentiometer wire balances the e.m.f. of

The lengths of the two pipes open at both ends are L and \((L+L_1)\). If they are sounded together, the beat frequency will be
(\(v\) = velocity of sound in air)

The number of waves counted by an observer on the sea-coast in one minute is 54. If the wavelength of the waves is \(5 \text{m}\) then the velocity of the waves in \(\text{m/s}\) will be

When a dipole placed parallel to electric field is rotating through \(π^c\), the work done is W. The work done in rotating the dipole through \((\frac{π}{3})^c\) is
(\(cos0^{\circ} = 1\), \(cos60^{\circ} = \frac{1}{2}\), \(cos180^{\circ} = -1\))

Fifth overtone of an open pipe of length \(L_0\) is in unison with the fifth overtone of the pipe closed at one end of length \(L_c\).
The ratio \(L_0\) to \(L_c\) is

A particle is performing simple harmonic motion about \(x = 0\) with an amplitude '\(a\)' and periodic time T. The speed of the particle at \(x = \frac{a}{3}\) will be

Which of the following graphs between pressure and volume of a gas correctly shows isochoric process in thermodynamics?

All the springs in fig (a), (b) and (c) are identical, each one having force constant K. Mass m is attached to each system. If \(T_a\), \(T_b\) and \(T_c\) are the periodic time of oscillations of the three systems in fig (a), (b) and (c) respectively, then

Two sources of sound are emitting progressive waves \(y_1 = 4sin708\,πt\) and \(y_2 = 3sin700\,πt\). The sources are placed close to each other. The number of beats heard per second and intensity ratio between waxing and wanning are respectively

The r.m.s. speed of hydrogen at S.T.P. is '\(u\)' \(\text{m/s}\). If the gas is heated at constant pressure till its volume becomes three times, the final temperature of the gas and the r.m.s. speed are respectively

An ideal gas is heated from \(27^{\circ}\text{C}\) to \(627^{\circ}\text{C}\) at constant pressure. If initial volume of gas is \(4 \text{m}^3\), then the new volume of the gas will be

A piston of cross-sectional area \(2.5\times 10^{-2} \text{m}^2\) is used in a hydraulic lift to exert a force of \(250 \text{N}\) on water. The cross-sectional area of the other piston which supports a car of mass \(3000 \text{kg}\) is (\(g = 9.8 \text{m/s}^2\))

In thermodynamic process for free expansion, select the 'WRONG' statement out of the following options.

The ratio of thermal conductivity of two rods of different materials is \(4:3\). The two rods have same area of cross-section and same thermal resistance. The lengths of rods are in the ratio