List of top Physics Questions

A \(70 \, \text{mH}\) inductor is connected to a \(220 \, \text{V}, 50 \, \text{Hz}\) AC supply. The RMS value of the current in the circuit is:

An isosceles triangular current-carrying loop is kept perpendicularly in a uniform magnetic field \( \vec{B}_0 \) as shown in the figure. The force on the loop due to magnetic field is:

A charged particle is moving in a uniform magnetic field and enters a lead layer, losing half of its kinetic energy. The radius of curvature of its path becomes:

A short bar magnet placed with its axis at \(45^\circ\) with a uniform external magnetic field of \(28.3 \times 10^{-3} \, \text{T}\) experiences a torque of magnitude \(3.6 \times 10^{-5} \, \text{J}\). The magnitude of magnetic moment of the magnet is nearly:

The quantities that don’t change when a resistor connected to a battery is heated due to the current are:

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 \(120\,\text{W}\)?

Among the following, the equation representing a progressive wave 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 \( A = 10 \, \text{Vm}^{-2} \))

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:

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).

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 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

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

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

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

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 ($K = 2 \, \text{N m}^{-3}$)

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

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$^{-2}$)

The dot product of unit vectors $\hat{n}_1$ and $\hat{n}_2$ that are parallel to $5\hat{i} + 12\hat{j}$ and $3\hat{i} + 4\hat{j}$ respectively 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$^{-2}$)