TAMIL NADU STATE BOARD CLASS 12 PHYSICS 2026

Two identical conducting balls having positive charges $q_1$ and $q_2$ are separated by a centre to centre distance $r$. If they are made to touch each other and then separated to the same distance, the force between them will be:

Two wires of A and B with circular cross section are made up of the same material with equal lengths. Suppose $R_A = 3R_B$, then what is the ratio of radius of wire A to that of B ?

A non conducting charged ring carrying a charge of $q$, mass $m$ and radius $r$ is rotated about its axis with constant angular speed $\omega$. The ratio of its magnetic moment with angular momentum is:

When the current changes from 12 A to $-2$ A in 0.05 s, an emf of 8 V is induced in a coil. The coefficient of self induction of the coil is:

Which one of them is used to produce a propagating electromagnetic wave ?

The speed of light in an isotropic medium depends on:

In a Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance $D$ must be changed to:

Emission of electrons by the absorption of heat energy is called _________ emission.

The mass of a $^{7}_{3}\mathrm{Li}$ nucleus is 0.042 u less than the sum of the masses of all its nucleons. The average binding energy per nucleon of $^{7}_{3}\mathrm{Li}$ nucleus is nearly:

The principle based on which a solar cell operates is:

The particle which gives mass to protons and neutrons are:

Which of the following statement is/are true for equipotential surface?

Inside the calcite crystal, along the optic axis, the ratio of velocities of extraordinary ray to ordinary ray is:

The range of the antenna is 64 km, then its height is (Radius of the earth is 6400 km):

If the focal length is 150 cm for a lens, what is the power of a lens?

Draw the schematic circuit diagram for a NPN transistor in common emitter configuration.

Light of wavelength of 5000 $\unicode{x212B}$ produces diffraction pattern of the single slit of width 5 $\mu$m. What is the maximum order of diffraction possible?

Write the applications of capacitors.

Two resistors when connected in series and parallel, their equivalent resistances are 15 $\Omega$ and $\frac{56}{15}\,\Omega$ respectively. Find the values of the resistances.

Define the current sensitivity of a galvanometer and how can it be increased?

Obtain an expression for average power of AC over a cycle.

What is Critical angle? Obtain the equation for Critical angle.

Mention the differences between Interference and Diffraction.

Show that nuclear density is almost constant for nuclei with Z > 10.

Give the circuit symbol, logic

Give the circuit symbol, logical operation, truth table and Boolean expression of AND gate.

When a light of frequency $9\times10^{14}$ Hz is incident on a metal surface, photoelectrons are emitted with a maximum speed of $8.14\times10^{5}$ ms$^{-1}$. Determine the threshold frequency of the surface.

(a) Derive an expression for electrostatic potential due to an electric dipole. OR (b) What is Fibre Optic Communication ? Write its merits and demerits.

(a) Explain the determination of unknown resistance using meter bridge. OR (b) List out the laws of photoelectric effect.

(a) Write down Maxwell equations in integral form. OR (b) Derive the equation for angle of deviation produced by a prism.

(a) Explain the working of cyclotron in detail. OR (b) (i) What are Polariser and Analyser ? (ii) List the uses of Polaroids.

(a) (i) What is binding energy of a nucleus ? Write its expression. (ii) Compute the binding energy of $^4_2$He nucleus using the following data : Atomic mass of Helium atom, $M_A$(He) = 4.00260 u, Mass of hydrogen atom, $m_H$ = 1.00785 u, and Mass of neutron, $m_n$ = 1.008665 u. OR (b) (i) Write about impedance of the series RLC circuit. (ii) Find the impedance of a series RLC circuit if the inductive reactance, capacitive reactance and resistance are 184 $\Omega$, 144 $\Omega$ and 30 $\Omega$ respectively. Also calculate the phase angle between voltage and current.