List of top Physics Questions

An electric lamp connected in series with a capacitor and an a.c source is glowing with certain brightness. On reducing the frequency of source the brightness of the lamp

A series resonant circuit consists of an inductor 'L' and capacitor 'C' which produces resonant frequency 'f'. If 'L' is increased by '2L' and 'C' is changed to '9C' the resonant frequency will be

A thin ring of radius 'R' metre has charge 'q' coulomb uniformly spread on it. The ring rotates about its axis with a constant frequency of 'f' revolution/s. The value of magnetic induction at the centre of the ring in \(\text{Wb/m}^2\) is

( \(μ_0\) = permeability of free space )

A long wire is bent into a circular coil of one turn and then into a circular coil of smaller radius having n turns. If the same current is passed in both the cases, the ratio of magnetic field produced at the centre for one turn to that of n turns is

A potentiometer wire is 4m long and potential difference of 2V is maintained between the ends. The e.m.f. of the cell which balances against a length of 80 cm of the potentiometer wire is

In metre bridge experiment, the resistance in the left gap is 15 \(\Omega\) and in the right gap is 45 \(\Omega\). The bridge is balanced. The distance of the null point from the centre of the wire is

An iron rod is placed parallel to magnetic field intensity 1000 A/m. The magnetic flux through the rod is \(3\times 10^{-4}\) Wb and its cross-sectional area is \(1.5 \text{cm}^2\). The magnetic permeability of rod in \(\text{Wb/}_{\text{A-m}}\) is

A charge moves in a circular path perpendicular to a magnetic field. The time period of revolution is independent of

Two parallel plate air capacitors are connected in parallel. Each capacitor has plate area \(A/2\) and separation between the plates is \(d\) and \(2d\) respectively. The equivalent capacity of the combination is

( \(ε_0\) = absolute permittivity of free space)

When open pipe is closed from one end then second overtone of closed pipe is higher in frequency by 100 Hz than first overtone of open pipe. The fundamental frequency of open end pipe will be (Neglect end correction)

Capacitors of capacities \(C_1\) and \(C_2\) are connected in series. If the combination is connected to a supply of V volt then the potential difference across capacitor \(C_2\) is

For a uniformly charged plane sheet, the variation of electric field (E) with distance (d) is correctly shown graphically in graph

A point charge 'Q' is placed at the centre of the line joining two equal charges '+q' and '+q'. The value of 'Q' when the system is in equilibrium is

A simple harmonic progressive wave is represented by \(y = Asin(120πt+3x)\). The distance between two points on the wave at a phase difference of \(\frac{π}{3}\) radian is

To increase the frequency of transverse oscillations of a stretched string by 40%, the tension must be increased by

A pipe open at both ends has a fundamental frequency 'f' in air. The pipe is dipped in water, so that \(\frac{2}{3}^{rd}\) length of pipe is in water, Now the fundamental frequency of the air column is

A body of mass \(0.4\) kg performs simple harmonic motion. It experiences a restoring force of \(0.4\) N when its displacement from the mean position is 4 cm. The force constant and magnitude of acceleration respectively are

A pendulum clock is running slow, In order to correct it, we should

The minimum phase difference between two simple harmonic motions is
\(x_1 = \frac{1}{\sqrt{2}}sinωt+\frac{1}{\sqrt{2}}cosωt\)
\(x_2 = sinωt+cosωt\)     \([sin\frac{π}{4} = cos\frac{π}{4} = \frac{1}{\sqrt{2}}]\)

In a cyclic process, work done by the system is

The average translational kinetic energy of a molecule in a gas is \(E_1\). The kinetic energy of the electron (e) accelerated from rest through potential difference 'V' volt is \(E_2\). The temperature at which \(E_1 = E_2\) possible is (N = number of molecules, R = gas constant)

An ideal gas is expanded adiabatically. How many times has the gas to be expanded to reduce the r.m.s. speed of molecules 3 times ? (\(γ = 1.5\))

The energy spectrum of a black body exhibits a maximum around a wavelength \(λ\). The temperature of a black body is now changed such that the energy is maximum at wavelength \(2λ/3\). The power radiated by the black body will now increase by a factor of

A black rectangular surface of area A emits energy E per second at \(127^{\circ}\)C. If length and breadth is reduced to half of initial value and temperature is raised to \(527^{\circ}\)C then energy emitted becomes

The ratio of the thermal conductivity of two rods of different materials is 6:5. The two rods of same area of cross section and same thermal resistance will have the length in the ratio