List of top Physics Questions

When two coaxial coils having the same current in the same direction are brought close to each other, then the value of current in both the coils:

A mixture consists of two radioactive materials \( A_1 \) and \( A_2 \) with half-lives of 20 s and 10 s respectively. Initially, the mixture has 40 g of \( A_1 \) and 160 g of \( A_2 \). The amount of the two in the mixture will become equal after

Two charged particles of the same charge but different masses \(m_1\) and \(m_2\) are projected with the same velocity \(V\) normally into the uniform magnetic field \(B\) as shown in the figure. The maximum separation of the particles is:

A block of metal 4 kg is in rest on a frictionless surface. It was targeted by a jet releasing water of 2 kg/s at a speed of 10 ms\(^{-1}\). The acceleration of the block is:

The time period of revolution of a satellite close to the planet’s surface is 80 minutes. The time period of another satellite which is at a height of 3 times the radius of the planet from the surface is:

A ball is projected at an angle of \( 45^\circ \) with the horizontal. It passes through a wall of height \( h \) at a horizontal distance \( d_1 \) from the point of projection and strikes the ground at a distance \( d_1 + d_2 \) from the point of projection, then \( h \) is:

Eddy currents are produced when

A cell of emf 1.2 V and internal resistance 2 \( \Omega \) is connected in parallel to another cell of emf 1.5 V and internal resistance 1 \( \Omega \). If the like poles of the cells are connected together, the emf of the combination of the two cells is:

In the hydrogen spectrum, the difference in frequencies of first and second Lyman lines is equal to the frequency of the second Balmer line. This corresponds to:

Two figures are shown as Fig. A and Fig. B. The time constant of Fig. A is \( \tau_A \), and time constant of Fig. B is \( \tau_B \). Then:

A train moves towards a stationary observer with speed 72 m/s\(^{-1}\). The train blows its horn and its frequency heard by observer is \(f_1\).
If the train speed is reduced to 36 m/s\(^{-1}\), the frequency heard by observer is \(f_2\). Then \( \frac{f_1}{f_2} \) is (given \(v = 340 { m/s}^{-1}\)):

A certain volume of a gas at 300 K expands adiabatically until its volume is doubled. The resultant fall in temperature of the gas is nearly (The ratio of the specific heats of the gas is 1.5)

A 4 kg mass is suspended as shown in the figure. All pulleys are frictionless and spring constant \( K \) is \( 8 \times 10^3 \) Nm\(^{-1}\). The extension in spring is ( \( g = 10 \) ms\(^{-2}\) )

A carrier is simultaneously modulated by two sine waves with modulation indices of 0.3 and 0.4; then the total modulation index is:

An information signal of frequency 10 kHz is modulated with a carrier wave of frequency 3.61 MHz. The upper side and lower side frequencies are:

The oxygen gas of 5 moles is heated at constant pressure from 300 K to 320 K. The amount of energy spent during this expansion is
(For oxygen \( C_p = 7 \, {Cal/mol} \cdot \degree C \), \( C_v = 5 \, {Cal/mol} \cdot \degree C \))

A body is executing simple harmonic motion. At a displacement \( x \), its potential energy is \( E_1 \), and at a displacement \( y \), its potential energy is \( E_2 \). The potential energy \( E \) at a displacement \( (x + y) \) is:

Two toroids with number of turns 400 and 200 have average radii respectively 30 cm and 60 cm. If they carry the same current, the ratio of magnetic fields in these two toroids is:

The gravitational field due to a mass distribution is \( E = \frac{K}{x^3} \) along x-direction (K is a constant). Taking the gravitational potential to be zero at infinity, its value at a distance \( x \) is:

When a mass \( m \) is connected individually to the springs \( s_1 \) and \( s_2 \), the oscillation frequencies are \( v_1 \) and \( v_2 \). If the same mass is attached to the two springs as shown in the figure, the oscillation frequency would be:

In a nuclear reactor, the fuel is consumed at the rate of \( 1 \times 10^{-3} \) gs\(^{-1}\). The power generated in kW is:

X and Y are two circuits having coefficient of mutual inductance 3 mH and resistances 10 \( \Omega \) and 4 \( \Omega \) respectively. To have induced current 60 \( \times 10^{-4} \, {A} \) in circuit Y, the amount of current to be changed in circuit X in 0.02 sec is:

As shown in the figure, a surface encloses an electric dipole with charges \( \pm6 \times 10^{-6} \, {C} \). The total electric flux through the closed surface is:

As shown in the figure, two blocks of masses \(m_1\) and \(m_2\) are connected to a spring of force constant \(k\). The blocks are slightly displaced in opposite directions to \(x_1, x_2\) distances and released. If the system executes simple harmonic motion, then the frequency of oscillation of the system (\(\omega\)) is:

Match the following (f is the number of degrees of freedom):

Monoatomic Diatomic (rigid) Diatomic Polyatomic (non-rigid)