List of top Physics Questions

If the wavelengths of maximum intensity of radiation emitted by two black bodies A and B are \( 0.5 \, \mu\text{m} \) and \( 0.1 \, \text{mm} \) respectively, then ratio of the temperatures of the bodies A and B is

When an ideal diatomic gas is heated at constant pressure, the fraction of the heat utilised to increase the internal energy of the gas is

The work done to increase the volume of 2 moles of an ideal gas from \( V \) to \( 2V \) at a constant temperature \( T \) is \( W \). The work to be done to increase the volume of 2 moles of the same gas from \( 2V \) to \( 4V \) at the same constant temperature \( T \) is:

In a Carnot engine, if the work done during isothermal expansion is 25% more than the work done during isothermal compression, then the efficiency of the engine is:

Water of mass 5 kg in a closed vessel is at a temperature of 20 , \(^\circ\text{C}\). If the temperature of the water when heated for a time of 10 minutes becomes \(30 \ , ^\circ\text{C}\), then the increase in the internal energy of the water is:

Obtain an expression for average power dissipated in a series LCR circuit.

An electric dipole is held in a uniform electric field. The dipole is aligned parallel to the electric field. Find the work done in rotating it through an angle of 180°.

A point charge \( q \) is placed at a distance \( d \) above an infinite, grounded conducting plate placed on the \( xy \)-plane at \( z = 0 \).
The electrostatic potential in the \( z > 0 \) region is given by \( \phi = \phi_1 + \phi_2 \), where:

\( \phi_1 = \frac{1}{4 \pi \epsilon_0} \cdot \frac{q}{\sqrt{x^2 + y^2 + (z - d)^2}} \)
\( \phi_2 = - \frac{1}{4 \pi \epsilon_0} \cdot \frac{q}{\sqrt{x^2 + y^2 + (z + d)^2}} \)

Which of the following option(s) is/are correct?

"If two systems are each in thermal equilibrium with a third system, they are also in thermal equilibrium with each other." This statement refers to :

State and prove the law of conservation of angular momentum.

Explain the classification of conductors, insulators and semiconductors on the basis of energy bands.

State and prove Kirchhoff's law of heat radiation.

What do you understand by polarized light ? When a third polaroid is rotated between two crossed polaroids, then discuss the change in the intensity of the transmitted light.

A lamp “50 watt and 100 volt” is to be connected to AC mains of 200 volt 50 Hz. Calculate the capacity of condenser required in series of lamp.

What do you mean by total internal reflection ? Show it by drawing ray diagram.

If 2 moles of an ideal monoatomic gas at a temperature of 27 °C is mixed with 4 moles of another ideal monoatomic gas at a temperature of 327 °C, then the temperature of the mixture of the two gases is

Find the maximum kinetic energy of the photo-electrons ejected, when light of wavelength 3300 Å is incident on a Cesium surface. Work function of Cesium = 1.9 eV.

For a Zener diode as shown in the circuit diagram below, the Zener voltage \(V_Z\) is 3.7 V. For a load resistance (\(R_L\)) of 1 k\(\Omega\), a current \(I_1\) flows through the load. If \(R_L\) is decreased to 500 \(\Omega\), the current changes to \(I_2\). The ratio \(\frac{I_2}{I_1}\) is \rule{1cm{0.15mm}. (up to two decimal places)}