List of top Physics Questions

Two cells of e.m.f. \(E_1\) and \(E_2\) (\(E_1 > E_2\)) are connected as shown in figure.

When a potentiometer is connected between points A and B the balancing length of potentiometer wire is \(412\) cm. When same potentiometer wire is connected between points A and C the balancing length is \(103\) cm. The ratio \(E_1:E_2\) is

The periodic time of a magnet in vibration magnetometer is \(T_0\). If a magnet is replaced by another magnet whose moment of inertia is three times and magnetic moment is one-third of the original magnet, then time period of new magnet will be

In meter bridge experiment, two resistances X and Y in the two gaps give a null point dividing the wire in the ratio \(2:3\). When each resistance is increased by \(30\,\Omega\), the null point divides the wire in the ratio \(5:6\). The resistance X and Y are respectively

A parallel plate air capacitor having area of each plate '\(A\)' and the distance between the plates '\(d\)' has uniform electric field E in the space between the plates. The energy stored in the capacitor is (\(ε_0\) = permittivity of free space.)

In a parallel plate air capacitor of plate separation '\(d\)', a dielectric slab of thickness '\(t\)' is introduced between the plates. The capacitance becomes one-third of the original value. The dielectric constant of the slab will be

Two point charges \(q_1\) and \(q_2\) are '\(l\)' distance apart. If one of the charges is doubled and the distance between them is halved. The magnitude of the force becomes 'n' times, where 'n' is

The 'Loudness' and 'Pitch' of sound respectively are the human perception to

A train is moving towards a stationary observer with speed \(34\) m/s. A train sounds a whistle of frequency \(450\) Hz. If the speed of sound is \(340\) m/s, the frequency heard by the observer in Hz is

A wire of length '\(L\)', diameter '\(d\)', density of material '\(ρ\)' is under tension '\(T\)' has fundamental frequency of vibration '\(n_A\)'. Another wire of length '\(2L\)', diameter '\(3d\)', density of material '\(2ρ\)' is vibrated under tension '\(2T\)', the fundamental frequency of vibration becomes '\(n_B\)'. The ratio \(n_B:n_A\) is

Four electric charges \(+q\) , \(+q\) , \(-q\) , and \(-q\) are placed in order at the corners of a square of side '\(2r\)'. The electric potential at a point midway between the two negative charges is

A tuning fork of frequency '\(n\)' is held near the open end of a tube which is dipped in water and length of the tube is adjusted until resonance occurs. If the two shortest lengths that produce resonance are \(l_1\) and \(l_2\), the speed of sound in air is (neglect end correction)

The ratio of the speed of sound in helium gas to that in nitrogen gas at \(295\) K is ( Ratio of specific heats \(γ\) for helium is \(\frac{5}{3}\) and that for nitrogen is \(\frac{7}{5}\). Molecular weight for helium and nitrogen are \(4\) and \(28\) respectively.)

A simple pendulum of length \(l_1\) has periodic time \(2.4\) s. Another simple pendulum of length \(l_2 < l_1\), has periodic time \(1.8\) s. The periodic time of simple pendulum of length \((l_1-l_2)\) is nearly

An ideal rigid diatomic gas \((γ = \frac{7}{5})\) undergoes an adiabatic change . If the relation between temperature and volume is \(TV^x =\) constant then the value of x is

Two springs of force constants '\(2k\)' and '\(k\)' are connected to a mass '\(m\)' as shown. Mass is displaced slightly to one side and released. The frequency of oscillation of the two springs-mass system is

Gas at pressure P, temperature T, and volume V is filled in jar A. Another jar B is filled with gas having parameters \(2P\), \(\frac{V}{4}\), \(2T\). The ratio of number of molecules of jar B to those of jar A is

A rigid diatomic gas \((γ = \frac{7}{5})\) is compressed adiabatically to volume \((\frac{V_i}{32})\), where \(V_i\) is the initial volume. The initial temperature of the gas is '\(T_i\)' K and the final temperature is '\(x\,T_i\)' K. The value of \(x\) is

Two oscillating simple pendulums with time periods \(T\) and \(\frac{4T}{3}\) are in phase at a given time. They will be again in phase after an elapse of time

The percentage decrease in the weight of a body when taken to a height of \(48\) km above the surface of the earth is (Radius of the earth is \(6400\) km)

In case of liquid, if Reynold's number '\(R_n\)' is \(1450\), then the flow of liquid will

If \(450\) erg of work is done in blowing a soap bubble of radius '\(r\)', the additional work required to be done to blow it to a radius equal to \(3r\) is

The excess pressure inside a soap bubble of radius \(2.5\) cm is \(48\) dyne/cm\(^2\). The surface tension of soap solution in dyne /cm is

A sphere is at temperature \(600\) K. In an external environment of \(200\) K, its cooling rate is R. When the temperature of the sphere falls to \(400\) K then cooling rate R' will become

Two rods of same length, radius and material transfer a given amount of heat in 't' second when they are joined as shown in fig (1). But when they are joined as shown in fig (2) then they will transfer same heat in same condition in time

The weight of man in lift moving in upward direction with an acceleration 'a' is \(660\) N. When the lift moves in the downward direction with the same acceleration, his weight is found to be \(380\) N. The real weight of the man when the lift is at rest is