List of top Physics Questions

A battery with a \(12\,\text{V}\) emf has an initial charge of \(80\,\text{A·h}\). If the potential across the terminals remains constant until it is fully discharged, how long can the battery deliver energy at a rate of \(120\,\text{W}\)?

A metal loop of area \(10 \, \text{cm}^2\) is placed in a region such that its area vector points along \( \hat{k} \). The region contains a uniform magnetic field of magnitude \(1.73 \, \text{T}\) that points in the direction \( \hat{i} + \hat{j} + \hat{k} \). When the magnetic field is switched off, the field decreases to zero at a steady rate in 10 seconds. The magnitude of emf induced in the loop is:

Among the following, the equation representing a progressive wave is:

A charge \( Q \) is to be divided between two objects. The values of the charges on the objects so that the electrostatic force between them will be maximum is:

A beam of light reflects and refracts at the surface between air and glass. The index of refraction of the glass is \(1.4\). If the refracted and reflected rays are perpendicular to each other, then the angle of incidence in the air is:

A ray of light is incident at \(30^\circ\) from a medium of refractive index 2 into a medium of refractive index 1. Then the angle of refraction is:

In a space having electric field \( \vec{E} = A(x\hat{i} + y\hat{j}) \), the potential at point (10 m, 20 m) is zero. Then the potential at the origin is: (Given \( A = 10 \, \text{Vm}^{-2} \))

Electric potential due to a space is given by: \[ \phi(x, y, z) = \phi_0 \cdot \frac{x_0}{x} \] where \( x_0 = 5\,\text{m}, \phi_0 = 8\,\text{V} \). Find the electric field at the point (10 m, 5 m, 5 m).

Energy needed in breaking a liquid drop of radius \( R \), into \( n \) smaller drops each of radius \( r \), is
[ \( T \) - Surface tension of the liquid ]

An object of mass \(10 \, \text{kg}\) is released from rest in a liquid. If the object moves a distance of \(2 \, \text{m}\) while sinking in a time duration of \(1 \, \text{s}\), then the mass of the liquid displaced by the submerged object is (Given: Acceleration due to gravity \( g = 10 \, \text{m/s}^2 \))

A Carnot engine operating between temperatures \( T_H = 600\,K \) and \( T_C = 300\,K \), absorbs \( Q_H = 800 \, \text{J} \) of heat from the source. The mechanical work done per cycle is:

A body cools down from \(75^\circ C\) to \(65^\circ C\) in 10 minutes. It will cool down from \(65^\circ C\) to \(55^\circ C\) in a time

The rms speed of oxygen at room temperature is about \(500 \, \text{m/s}\). The rms speed of hydrogen at the same temperature is about

A copper wire of length 2.4 m and an aluminum wire of length 0.7 m, both having diameter 2 mm, are connected end to end. When stretched by a load, the obtained elongation is found to be 0.6 mm. The applied load is
(Given: Young’s modulus of copper \( Y_C = 1.2 \times 10^{11} \, \text{Nm}^{-2} \), Young’s modulus of aluminum \( Y_A = 0.7 \times 10^{11} \, \text{Nm}^{-2} \))

The angular momentum of a wheel having a rotational inertia of \( 0.2 \, \text{kg} \, \text{m}^2 \) about its symmetric axis decreases from \( 4 \) to \( 2 \, \text{kg} \, \text{m}^2 \, \text{s}^{-1} \) in \( 4 \, \text{s} \). The average power of the wheel is

Consider a force $F = K x^3$ which acts on a particle at rest. The work done by the force for the displacement of 2 m is ($K = 2 \, \text{N m}^{-3}$)

An object of mass 3 kg is tied by a string of negligible mass to a ceiling and held such that the string is taut. The object is released suddenly such that the string remains taut. It’s acceleration when released is (acceleration due to gravity = 10 m s$^{-2}$)

A pendulum is oscillating at a frequency of \( 8 \, \text{Hz} \). Suddenly the string of the pendulum is clamped at its midpoint. Then the new frequency of oscillations is

Time period of a simple pendulum is \( 4 \, \text{s} \) at a place on the earth where the acceleration due to gravity is \( \pi^2 \, \text{m/s}^2 \). Then the length of the pendulum in meters is

The centre of mass of a homogeneous semi-circular plate of radius $r$ is located at A as shown in the figure. The distance $OA$ is

Two planets, A and B, orbit around a star such that the time period of A is 8 times the time period of B. The ratio of orbital velocities of the planets A and B is

A force $\vec{F} = 4\hat{i} - 15\hat{j}$ N acts on a body resulting in a displacement of $6\hat{i}$. If the body had kinetic energy of 7 joules at the beginning of the displacement, the kinetic energy at the end of the displacement is

When a ball is dropped from a height $h$ it takes $t$ sec to reach the ground. If the same experiment is done on a different planet having the mass 100 times the earth’s mass and radius 10 times the earth’s radius, then the time it will take to cover the same height $h$ is

At the moment $t = 0$, a time dependent force $F = at$ (where $a$ is constant equal to 1 N s$^{-1}$) is applied on a body of mass 1 kg resting on a smooth horizontal plane as shown in the figure. If the direction of this force makes an angle $45^\circ$ with the horizontal, then the velocity of the body at the moment it leaves the plane is (acceleration due to gravity = 10 m s$^{-2}$)

A sphere rolls down from the top of an inclined plane which makes an angle $30^\circ$ with the edge of a horizontal roof of a house. If the highest and lowest points of the inclined plane are 8.75 m and 3.75 m respectively from the ground then the horizontal distance from the lower edge of the roof at which the sphere hits the ground is (acceleration due to gravity = 10 m s$^{-2}$)