List of top Questions asked in Maharashtra Class XII

Prove that the frequency of beats is equal to the difference between the frequencies of the two sound notes giving rise to beats.
Define:
(a) Inductive reactance
(b) Capacitive reactance
(c) Impedance
Plane wavefront of light of wavelength 6000 Å is incident on two slits on a screen perpendicular to the direction of light rays. If the total separation of 10 bright fringes on a screen 2 m away is 2 cm, find the distance between the slits.
Eight droplets of water each of radius 0.2 mm coalesce into a single drop. Find the decrease in the surface area.
A 0.1 H inductor, a 25 × 10\(^{-6}\) F capacitor, and a 15 Ω resistor are connected in series to a 120 V, 50 Hz AC source. Calculate the resonant frequency.
The difference between the two molar specific heats of a gas is 9000 J/kg K. If the ratio of the two specific heats is 1.5, calculate the two molar specific heats.
What are harmonics and overtones (Two points)?
Distinguish between potentiometer and voltmeter.
What are mechanical equilibrium and thermal equilibrium?
An electron in an atom is revolving round the nucleus in a circular orbit of radius 5.3 × 10\(^{-11}\) m with a speed of 3 × 10\(^6\) m/s. Find the angular momentum of electron.
Define moment of inertia of a rotating rigid body. State its SI unit and dimensions.
What are polar dielectrics and non-polar dielectrics?
What is a thermodynamic process? Give any two types of it.
Derive an expression for the radius of the \( n \)-th Bohr orbit of the electron in hydrogen atom.
What is the mathematical formula for third postulate of Bohr's atomic model?
Two inductor coils with inductance 10 mH and 20 mH are connected in series. What is the resultant inductance of the combination of the two coils?
Calculate the moment of inertia of a uniform disc of mass 10 kg and radius 60 cm about an axis perpendicular to its length and passing through its centre.
State the formula for critical velocity in terms of Reynold's number for a flow of a fluid.
Is it always necessary to use red light to get photoelectric emission?
Write the Boolean expression for Exclusive-OR (XOR) gate.
Write the differential equation for angular S.H.M.
In Young's double slit experiment the two coherent sources have different amplitudes. If the ratio of maximum intensity to minimum intensity is 16 : 1, then the ratio of amplitudes of the two sources will be ______.
The equation of a simple harmonic progressive wave travelling on a string is \( y = 8 \sin (0.02 x - 4 t) \) cm. The speed of the wave is ______.
Define potential gradient of the potentiometer wire.
The unit Wbm\(^2\) is equal to ______.