List of top Physics Questions

The sum of the magnitudes of two vectors $\vec{A$ and $\vec{B}$ is $8$ and magnitude of the resultant is $4$. If the resultant vector is perpendicular to any one vector, then the magnitudes of the two vectors $\vec{A}$ and $\vec{B}$ are}

A disc of mass $10\,\text{kg$ and radius $0.1\,\text{m}$ is rotating at $120\,\text{r.p.m.}$. A retarding torque brings it to rest in $10\,\text{s}$. If the same torque is due to force applied tangentially on the rim of the disc, then the magnitude of force is}

If only $2%$ of the total current passes through an ammeter having coil of resistance $R$, then the resistance of the shunt of an ammeter is

A force of $10\,\text{N$ is required to break a wire of radius $1\,\text{mm}$. The force required to break the wire of same material but radius $3\,\text{mm}$ will be}

A train blowing the whistle moves with a constant velocity $V$ away from an observer standing on the platform. The ratio of the natural frequency of the whistle $n$ to the apparent frequency is $1.2:1$. If the train is at rest and the observer moves away from it at the same velocity $V$, the ratio of $n$ to the apparent frequency is

A Diwali cracker releases $25$ gram gas per second, with a speed of $400\,\text{m s^{-1}$ after explosion. The force exerted by gas on the cracker is}

A body performs linear simple harmonic motion of amplitude $A$. At what displacement from the mean position, the potential energy of the body is one fourth of its total energy?

Light travels from an optically denser medium $A$ into the optically rarer medium $B$ with speeds $1.8\times10^8\,\text{m s^{-1}$ and $2.7\times10^8\,\text{m s}^{-1}$ respectively. The critical angle between them is ($\mu_1$ and $\mu_2$ are the refractive indices of media $A$ and $B$ respectively)}

The errors in the measurement of mass and length of the cube is $1.5%$ and $2.5%$ respectively. The percentage error in the measurement of density of a cube is

Photons of wavelength $\lambda$ are incident on the cathode of a photocell. Electrons are emitted from the cathode surface. The de-Broglie wavelength of the emitted electrons (work function is negligible) is
$\left(c = \text{velocity of light},\; h = \text{Planck’s constant},\; m = \text{mass of electron}\right)$

The period of revolution of a satellite is

When the work function of a metal increases, maximum kinetic energy of emitted photoelectrons

A cyclotron’s oscillator frequency is $n$ and radius of the dees is $r$. The operating magnetic field $(B)$ for accelerating protons of charge $q$ and kinetic energy of protons produced by the accelerator is respectively ($m$ and $v$ be the mass and velocity of proton)

A wire carrying current $I$ along x-axis has length $\ell$ and is kept in a magnetic field $\vec{B=(\hat{i}+2\hat{j}-3\hat{k})\,\text{Wb m}^{-2}$. The magnitude of magnetic force acting on the wire is}

Two small drops of liquid of same radius coalesce to form a big drop. The ratio of the total surface energies after and before the change is

A stationary wave is formed having 4 nodes along the $120\,\text{cm$ length of the string. The wavelength of the wave is}

A pendulum is oscillating with frequency $n$ on the surface of earth. It is taken to depth $\dfrac{R{2}$ below the surface of earth where $R$ is radius of earth. The new frequency of oscillations at depth $\dfrac{R}{2}$ is}

A block of mass $m$, kept on a horizontal surface, is moved through a distance $s$ by applying a horizontal force $F$ to it. What is the work done by the normal reaction?

Water is flowing through a horizontal pipe of non-uniform cross-section. In the region of narrowest part inside the pipe, the water will have

A parallel beam of monochromatic light of wavelength $5\times10^{-7\,\text{m}$ is incident normally on a single narrow slit of width $10^{-3}\,\text{mm}$. At what angle of diffraction, the first minima is observed?}

The digital signals are used for transmission in communication system. They are

A string of mass $0.1\,\text{kg$ is under a tension $1.6\,\text{N}$. The length of the string is $1\,\text{m}$. A transverse wave starts from one end of the string. The time taken by the wave to reach the other end is}

For a particle performing S.H.M., the displacement–time graph is as shown.

In biprism experiment, a source of monochromatic light is used for a certain distance between slit and eyepiece. When the distance between two virtual sources is changed from $d_A$ to $d_B$, then the fringe width is changed from $Z_A$ to $Z_B$. The ratio $Z_A$ to $Z_B$ is

Two identical thin bar magnets are placed mutually at right angles such that the north pole of one touches the south pole of the other. The length of each bar magnet is $\ell$. The magnitude of resultant magnetic moment of the system is
$\left[m = \text{pole strength of the magnet}\right]$