List of top Physics Questions asked in CBSE CLASS XII

An object is placed between the pole and the focus of a concave mirror. Using mirror formula, prove mathematically that it produces a virtual and enlarged image.
Discuss briefly diffraction of light from a single slit and draw the shape of the diffraction pattern.
Establish the expression for impedance of the circuit when elements X, Y, and Z are connected in series to an AC source. Show the variation of current in the circuit with the frequency of the applied AC source.
The dipole moment of a molecule is \( 10^{-30} \, \text{Cm} \). It is placed in an electric field \( \vec{E} \) of \( 10^5 \, \text{V/m} \) such that its axis is along the electric field. The direction of \( \vec{E} \) is suddenly changed by \( 60^\circ \) at an instant. Find the change in the potential energy of the dipole, at that instant.
A ray of light is incident normally on a prism ABC of refractive index \( \sqrt{2} \), as shown in the figure. After it strikes face AC, it will
A ray of light is incident normally
Draw equipotential surfaces for an electric dipole.
equipotential surfaces for an electric dipole.
You are given three circuit elements X, Y, and Z. They are connected one by one across a given ac source. It is found that \( V \) and \( I \) are in phase for element X. \( V \) leads \( I \) by \( \frac{\pi}{4} \) for element Y while \( I \) leads \( V \) by \( \frac{\pi}{4} \) for element Z. Identify elements X, Y, and Z.
Two long straight thin wires AB and CD have linear charge densities \( 10 \, \text{mC/m} \) and \( -20 \, \text{mC/m} \), respectively. They are kept parallel to each other at a distance of 1 m. Find the magnitude and direction of the net electric field at a point midway between them.
Two point charges \( q_1 \) and \( q_2 \), are located at \( \vec{r_1} \) and \( \vec{r_2} \) respectively in an external electric field \( \vec{E} \). Obtain an expression for the potential energy of the system.
Three beams of red, yellow, and violet colours are passed through a prism, one by one under the same condition. When the prism is in the position of minimum deviation, the angles of refraction from the second surface are \( r_R \), \( r_Y \), and \( r_V \) respectively. Then,
The critical angle for a ray of light passing from glass to water is minimum for
Two capacitors of capacitances \( 2C_0 \) and \( 6C_0 \), are first connected in series and then in parallel across the same battery. The ratio of energies stored in series combination to that in parallel is:
An air-filled capacitor with plate area A and plate separation d has capacitance \( C_0 \). A slab of dielectric constant K, area A and thickness \( \frac{d}{5} \) is inserted between the plates. The capacitance of the capacitor will become:
When a ray of light of wavelength \( \lambda \) and frequency \( \nu \) is refracted into a denser medium,
The critical angle for glass is \( \theta_1 \) and that for water is \( \theta_2 \). The critical angle for the glass-water surface would be (given \( \mu_g = 1.5 \), \( \mu_w = 1.33 \)):
Which of the following statements about dielectrics is correct?
Explain the characteristics of a p-n junction diode that makes it suitable for its use as a rectifier.
With the help of a circuit diagram, explain the working of a full wave rectifier.
A doped semiconductor is electrically neutral.
In a p-n junction under equilibrium, there is no net current.
When a dielectric slab is inserted between the plates of an isolated charged capacitor, the energy stored in it:
State Lenz's Law. In a closed circuit, the induced current opposes the change in magnetic flux that produced it as per the law of conservation of energy. Justify.
A metal rod of length 2 m is rotated with a frequency of 60 rev/s about an axis passing through its centre and perpendicular to its length. A uniform magnetic field of 2T perpendicular to its plane of rotation is switched-on in the region. Calculate the e.m.f. induced between the centre and the end of the rod.
Two long straight parallel wires separated by 20 cm carry 5 A and 10 A current respectively, in the same direction. Find the magnitude and direction of the net magnetic field at a point midway between them.
State and explain Ampere’s circuital law.