List of top Physics Questions

In amplitude modulation, the amplitude of the carrier signal is 28 V and the modulation index is 0.4. The amplitude of the side bands is:

The following statement is true in case of total internal reflection:

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:

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:

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 \(v = 340 { m/s}^{-1}\)):

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:

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:

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

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)

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 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\(^{-2}\) )

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:

When the load applied to a wire is increased from 5 kg wt to 8 kg wt, the elongation of the wire increases from 1 mm to 1.8 mm. The work done during the elongation of the wire is (Acceleration due to gravity = 10 m/s\(^2\)):

A car is moving on a horizontal curved road of radius 50 m. If the friction coefficient between tyres and road is 0.34, the approximate maximum speed of the car will be nearly:

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:

The current passing through a coil of 120 turns and inductance \( 40 \) mH is \( 30 \) mA. The magnetic flux linked with the coil is:

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

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

Which of the following is NOT a unit of permeability?

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:

The electric field for an electromagnetic wave is given by \( E = 40 \sin(kz - 6 \times 10^8 t) \), where the magnitude of \( E_0 \) is in V/m.
The magnitude of the wave vector \( k \) is