List of top Physics Questions

A long solenoid has $1000$ turns. When a current of $4\,A$ flows through it, the magnetic flux linked with each turn of the solenoid is $4 \times 10^{-3} \, Wb$. The self-inductance of the solenoid is :
Identify the correct statement about a stationary wave
A solid cylinder of radius $R$ made of a material of thermal conductivity $K_1$ is surrounded by a cylindrical shell of inner radius $R$ and outer radius $2R$ made of a material of thermal conductivity $K_2$. The two ends of the combined system are maintained at two different temperatures. Then there is no loss of heat across the cylindrical surface and the system is in steady state. The effective thermal conductivity of the system is
Assuming the expression for the pressure exerted by the gas on the walls of the container, it can be shown that pressure is
For an ideal step-down transformer, the quantity which is constant for both the coils is
If the ratio of the mechanical energy of a mass whose oscillations are damped to that of its free oscillations is $ e^{-3 t/m} $ , then the ratio of the amplitudes of the damped oscillations to that of free oscillations is
If the coefficient of linear expansion of a metal is $ 0.00002 \,K^{-1} $ , then the necessary increase in temperature of the metal rod in order to increase its length by $ 2\% $ is
The processes $ 3, 2 $ and $ 1 $ represent the respective isobaric, isothermal and adiabatic expansion of one mole of a gas initially at a pressure $ P $ from volume $ V $ to $ 2V $ . The work done is
For an object placed in front of a convex mirror of focal length $ f $ , its image is formed
The temperature of source of a Carnot engine of efficiency $ 20\% $ when the heat exhausted is at $ 240 \,K $ is
In shown fig, the circular loop of wire is moved with velocity towards the infinite current carrying wire. Then
Two charges of equal amount +Q are placed on a line. Another charge q is placed at the mid-point of the line. The system will be in equilibrium if the value of q is
The increase in electrostatic potential energy of a dipole of moment p when it is taken from parallel to anti-parallel orientation in an electric field E is
A micro-ammeter gives full scale deflection at 100 $\mu$A. Its resistance is 2k$\Omega$. The resistance required to convert it to a voltmeter reading 1V is
A particle of mass ????and carrying a charge ????enters with a velocity ????perpendicular to a uniform magnetic field. The time period of rotation of the particle
If$I_{1}$and$I_{2}$ be the sizes of real images for two positions of a convex lens between object and screen,then the size of the object is
If a bar magnet of magnetic moment M is kept in a uniform magnetic field B, its time period of oscillation is T. In the same magnetic field, the time period of another magnet of same dimension and same mass but of moment M/4 is,
If $i_1 = 3 \, \sin \, \omega t$ and $i_2 = 4 \, \cos \, \omega t$, then $i_3$ is
Hologram is based on phenomenon of
For a current carrying inductor, emf associated is 20mV. Now, current through it changes from 6A to 2A in 2s. The coefficient of mutual inductance is
If the nuclear radius of $^{27}Al$ is 3.6 Fermi, the approximate nuclear radius of $^{64}Cu$ in Fermi is
A layer of oil with density $724\, kg/m^3$ floats on water of density $1000\, kg/m^3$. A block floats at the oil-water interface with $1/6$ of its volume in oil and $5/6$ of its volume in water, as shown in the figure. What is the density of the block?
An n-p-n transistor of current gain 80 in common emitter mode gives emitter current equal to 8.1 mA. The base current is
Two solenoids are given - 1st has 1 turn per unit length and 2nd has n turns per unit length. Ratio of magnetic fields at their centres is
Which statement is correct for the given circuit?