List of top Physics Questions

A charged particle moving in a uniform magnetic field and losses $4\%$ of its kinetic energy. The radius of curvature of its path changes by
The masses of blocks $A$ and $B$ are $m$ and $M$ respectively. Between $A$ and $B$, there is a constant frictional force $F$ and $B$ can slide on a smooth horizontal surface. $A$ is set in motion with velocity while $B$ is at rest. What is the distance moved by $A$ relative to $B$ before they move with the same velocity?
The efficiency of fuel cell is given by the expression, $\eta$ is
A solid sphere of radius $R$ has a charge $Q$ distributed in its volume with a charge density $\rho=k r^{a}$, where $k$ and a are constants and $r$ is the distance from its center. If the electric field at $r =\frac{R}{2}$ is times that at $r = R$, the value of $a$ is
A thin rod of length $4l$, mass $4\, m$ is bent at the points as shown in figure. What is the moment of inertia of the rod about the axis passing point $O$ and perpendicular to the plane of the paper?
At the corners of an equilateral triangle of side a ( $1$ meter), three point charges are placed (each of $0.1\, C$ ). If this system is supplied energy at the rate of $1\, kw$, then calculate the time required to move one of the mid-point of the line joining the other two.
In $CE$ transistor amplifier, the audio signal voltage across the collector resistance of $2\, k \Omega$ is $2\, V$. If the base resistance is $1\, k \Omega$ and the current amplification of the transistor is $100$, the input signal voltage is
Two tuning forks with natural frequencies $340\,Hz$ each move relative to a stationary observer. One fork moves away from the observer, while the other moves towards the observer at the same speed. The observer hears beats of frequency $3\, Hz$. Find the speed of the tuning forks.
Two polaroids are kept crossed to each other. If one of them is rotated an angle $60^{\circ}$, the percentage of incident light now transmitted through the system is
The refractive index for a prism is given as $\mu = \cot \frac{A}{2}$. Then, angle of minimum deviation in terms of angle of prism is
A particle of mass m is driven by a machine that delivers a constant power k watts. If the particle starts from rest the force on the particle at time t is
A $2\,kg$ mass lying on a table is displaced in the horizontal direction through $50\,cm$. The work done by the normal reaction will be
Consider a thin uniform square sheet made of a rigid material. If its side is '$a$', mass $m$ and moment of inertia $I$ about one of its diagonals, then :
From a solid sphere of mass $M$ and radius $R$, a spherical portion of radius $\frac{R}{2}$ is removed, as shown in the figure. Taking gravitational potential $V = 0$ at $r = \infty$, the potential at the centre of the cavity thus formed is ($G =$ gravitational constant)
A very long (length L) cylindrical galaxy is made of uniformly distributed mass and has radius $R (R << L)$. A star outside the galaxy is orbiting the galaxy in a plane perpendicular to the galaxy and passing through its centre. If the time period of star is $T$ and its distance from the galaxy's axis is $r$, then :
A pendulum made of a uniform wire of cross sectional area $A$ has time period $T$. When an additional mass $M$ is added to its bob, the time period changes to $T_M$. If the Young's modulus of the material of the wire is $Y$ then $\frac{1}{Y}$ is equal to ( $g =$ gravitational acceleration)
A simple harmonic oscillator of angular frequency $2 \,rad \,s^{-1}$ is acted upon by an external force $F= \sin\, t \,N$. If the oscillator is at rest in its equilibrium position at $t\, =\, 0$, its position at later times is proportional to :
A ball is projected up at an angle $\theta$ with horizontal from the top of a tower with speed $v$. It hits the ground at point $A$ after time $t_{A}$ with speed $v_{A}$ . Now, this ball is projected at same angle and speed from the base of the tower (located at point $P$) and it hits ground at point $B$ after time $t_{B}$ with speed $v_{B}$. Then
Two stones are thrown up simultaneously from the edge of a cliff $240\, m$ high with initial speed of $10\, m/s$ and $40\, m/s$ respectively. Which of the following graph best represents the time variation of relative position of the second stone with respect to the first? (Assume stones do not rebound after hitting the ground and neglect air resistance, take $g=10\, m/s^2$)
A thin convex lens of focal length ' $f'$ is put on a plane mirror as shown in the figure. When an object is kept at a distance ' $a$ ' from the lens-mirror combination, its image is formed at a distance $\frac{a}{3}$ in front of the combination. The value of ' $a$ ' is
You are asked to design a shaving mirror assuming that a person keeps it $10\,cm$ from his face and views the magnified image of the face at the closest comfortable distance of $25\, cm$. The radius of curvature of the mirror would then be :
In an ideal gas at temperature $T$, the average force that a molecule applies on the walls of a closed container depends on $T$ as $T^q$. A good estimate for $q$ is :
For plane electromagnetic waves propagating in the $z$ direction, which one of the following combination gives the correct possible direction for $\vec{E}$ and $\vec{B}$ field respectively ?
A train is moving on a straight track with speed $20\, ms^{-1}.$ It is blowing its whistle at the frequency of $1000\, Hz$. The percentage change in the frequency heard by a person standing near the track as the train passes him is close to (speed of sound $= 320\,ms^{-1}$)
A uniform solid cylindrical roller of mass '$m$' is being pulled on a horizontal surface with force $F$ parallel to the surface and applied at its centre. If the acceleration of the cylinder is '$a$' and it is rolling without slipping then the value of '$F$' is :