List of top Physics Questions

Double convex lens has radii of curvature 4 cm and 8 cm. Refractive index = 1.5. Find focal length.
Assertion (A): In constant potential region, electric field is zero. Reason (R): From Gauss’s Law, zero electric field means zero enclosed charge.
In non-rigid diatomic molecules with an additional vibrational mode: \( C_P \) and \( C_V \) become:
Speed of sound in air near room temperature is approximately:
In a U-tube with radii 2 mm and 4 mm, surface tension = 0.03 N/m, density = 1500 kg/m\(^3\), contact angle = 0. Height difference in limbs is:
A metal tape calibrated at \( 25^\circ C \) is used at \( -15^\circ C \). Coefficient of linear expansion is \( 1 \times 10^{-5}\ /\ ^\circ C \). Find percentage error in measurement.
A gas goes through: (i) isothermal expansion \( W = 50J \), (ii) adiabatic \( W = ? \), (iii) isothermal expansion \( W = 20J \). Total \( \Delta U = -30J \). Find work in adiabatic.
A Carnot engine has sink at 250 K. If efficiency increases from 25% to 50%, by how much must sink’s temperature increase?
Two balls A (mass M) and B (mass 2M) collide elastically. If A moves at 150 m/s and comes to rest, find velocity of B before collision. \( e = 1 \).
A hydraulic lift has two pistons: 3 cm and 5 cm. A 1875 kg mass is lifted. Find force on small piston. \( g = 10\ \text{m/s}^2 \)
A body is executing S.H.M. At a displacement \( x \), its potential energy is 9 J and at displacement \( y \), its potential energy is 16 J. The potential energy at displacement \( (x + y) \) is:
An iron block A of volume \( 0.25\ \text{m}^3 \) stretches a spring by 0.2 m. A new block B of volume \( 0.75\ \text{m}^3 \) is kept on a frictionless incline (30°) using same spring. Find equilibrium distance along incline.
An iron block A of volume 0.25 m3
A solid sphere of radius R has its outer half removed to become radius \( \frac{R}{2} \). What is the moment of inertia about its diameter?
A ball follows the vertical displacement \( y = (Pt^2 - Qt^3) \), where \( y \) is in meters. Find the maximum height the ball can reach.
An object moving along x-axis with a uniform acceleration has velocity \( \vec{V} = (12\ \text{cm/s})\hat{i} \) at \( x = 3\ \text{cm} \). After 2 s, if it is at \( x = -5\ \text{cm} \), then its acceleration is:
A cricket ball of mass 50 g and velocity 50 cm/s is stopped in 0.5 s. What is the force applied?
Two masses \( M_1 \) and \( M_2 \) are arranged as shown. If \( a \) is the acceleration of the system, and \( M_1 \) is doubled, \( M_2 \) halved, then new acceleration is:
Two masses M1 and M2 are arranged as shown
A ball of mass 300 g is dropped from a height of 10 m and penetrates 1.5 m into sand. Find the average resistance by the sand. Take \( g = 10\ \text{m/s}^2 \).
Two forces of magnitude 4 N act on an object of mass 1 kg: \( \vec{F}_1 \) at 30° to x-axis and \( \vec{F}_2 \) along y-axis. Find the magnitude of acceleration.
In SI units, \( \text{kg m}^2 \text{s}^{-2} \) is equivalent to which of the following?
A light from Paschen series of hydrogen atom is able to eject photoelectrons from a metal. Then the work function of the metal is
The average number of photons emitted per second by a laser of power \(6.6 \times 10^{-3}\) W producing a light of wavelength 600 nm is (Planck’s constant, \(h = 6.6 \times 10^{-34}\) J·s)
The average number of photons emitted per second by a laser of power \(6.6 \times 10^{-3}\) W producing a light of wavelength 600 nm is (Planck’s constant, \(h = 6.6 \times 10^{-34}\) J·s)
A light from Paschen series of hydrogen atom is able to eject photoelectrons from a metal. Then the work function of the metal is
The average number of photons emitted per second by a laser of power \(6.6 \times 10^{-3}\) W producing a light of wavelength 600 nm is (Planck’s constant, \(h = 6.6 \times 10^{-34}\) J·s)