List of top Physics Questions

In a potentiometer of one- metre length, an unknown emf voltage source is balanced at $60 \,cm$ length of potentiometer wire, while a $3 \,V$ battery is balanced at $45 \,cm$ length. Then the emf of the unknown voltage source is
A galvanometer of resistance $10\, \Omega$ gives full-scale deflection when $1\, mA$ current passes through it. The resistance required to convert it into a voltmeter reading upto $2.5\, V$ is
Ideal voltmeter connected as shown reads
If on applying the potential of 20 V on a conductor its conductance becomes $ 8\,{{(\Omega )}^{-1}}, $ then the current flowing through it will be
A conducting rod of length $l$ and mass $m$ is moving down a smooth inclined plane of inclination $\theta$ with constant velocity $v$. A current $i$ is flowing in the conductor in a direction perpendicular to paper inwards. A vertically upwards magnetic field $\vec{ B }$ exists in space. Then magnitude of magnetic field $\vec{ B }$ is
The value of current J in the circuit will be
The resistance of mercury at $4.2 \, K$ is
A particle executes simple harmonic oscillation with an amplitude $a$. The period of oscillation is $T$ . The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is
The mass $M$ shown in the figure oscillates in simple harmonic motion with amplitude $A$. The amplitude of the point $P$ is
A uniform rod of length $L$ and mass $M$ is pivoted at the centre. Its two ends are attached to two springs of equal spring constants $k$. The springs are fixed to rigid supports as shown in the figure, and rod is free to oscillate in the horizontal plane. The rod is gently pushed through a small angle $\theta$ in one direction and released. The frequency of oscillation is
A body executing linear simple harmonic motion has a velocity of $3\, ms ^{-1}$ when its displacement is $4\, cm$ and a velocity of $4\, ms ^{-1}$ when its displacement is $3 cm$. What is the amplitude of oscillation ?
A body executes simple harmonic motion under the action of force $F_{1}$ with a time period $\frac{4}{5} s$. If the force is changed to $F_{2}$ it executes simple harmonic motion with time period $\frac{3}{5} s$. If both forces $F_{1}$ and $F_{2}$ act simultaneously in the same direction on the body, its time period will be
A block is resting on a piston which is moving vertically with SHM of period $1\, s$ . At what amplitude of motion will the block and piston separate?
Two simple harmonic motions are given by $ x=A\sin (\omega t+\delta ) $ and $ y=A\sin \left( \omega t+\delta +\frac{\pi }{2} \right) $ act on a particle simultaneously, then the motion of particle will be
The bob of a simple pendulum is a ball full of water, if a fine hole is made in the bottom of the ball, the time period first increases and then decreases. As water flows out of the bob the weight of bob decreases.
The reiation between electric field vector E, the displacement vector D and the polarization vector P for a dielectric placed in electric field E is given by
A charge $Q$ is placed at each of the opposite corners of a square. A charge $q$ is placed at each of the other two corners. If the net electrical force on $Q$ is zero, then the $Q/q $ equals
The surface charge density (in $ Cm^{-2} $ ) of the earth is about
Under the influence of the coulomb field of charge $+\,Q$, a charge $-\,q$ is moving around it in an elliptical orbit. Find out the correct statement(s).
Gausss law is valid for
Figure below show regular haxagons, with charges at the vertices. In which case is the electric field at the centre zero ?
A charge $Q$ is uniformly distributed over a large square plate of copper. The electric field at a point very close to the centre of the plate is 10 $ Vm^{ -1}$. If the copper plate is replaced by a plastic plate of the same geometrical dimensions and carrying the same charge $Q$ uniformly distributed, then the electric field at the point $P$ will be
A pendulum bob of mass $m$ carrying a charge $q$ is at rest with its string making an angle $\theta$ with the vertical in a uniform horizontal electric field $E$. The tension in the string is
Four charges are arranged at the corners of a square as shown in the figure. The direction of electric field at the centre of the square is along
The excess pressure inside a cylindrical drop of liquid or a cylindrical bubble of radius $r$ in a liquid of surface tension $T$ is