List of top Physics Questions

The dimensional formula of permeability of free space $\mu_0$ is
The depletion layer in the p-n junction region is caused by
A uniform magnetic field acts right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of electrons is doubled, then the radius of the circular path will be
A 100 millihenry coil carries a current of 1 A. Energy stored in its magnetic field is
The angular velocity and the amplitude of a simple pendulum is $\omega$ and a respectively. At a displacement x from the mean position if its kinetic energy is T and potential energy is V, then the ratio of T to V is
If the number of turns per unit length of a coil of solenoid is doubled, the self-inductance of the solenoid will
A magnetic field of $2\times 10^{-2}$T acts at right angles to a coil of area 100 $cm^2$, with 50 turns. The average e.m.f. induced in the coil is 0.1 V, when it is removed from the field in t sec. The value of t is
The velocity of charge carriers of current (about 1 ampere) in a metal under normal conditions is of the order of
Faraday's laws are consequence of conservation of
In the nucleus of $_{11}Na^{23}$ , the number of protons, neutrons and electrons are
A certain body weighs $22.42\,g$ and has a measured volume of $4.7\,cc$. The possible error in the measurement of mass and volume are $0.01\,gm$ and $0.1\,cc$. Then maximum error in the density will be
A body is executing simple harmonic motion. When the displacements from the mean position is $4 \,cm$ and $5 \,cm$, the corresponding velocities of the body is $10 \,cm/sec$ and $8\, cm/sec$. Then the time period of the body is
A heavy uniform chain lies on horizontal table top. If the coefficient of friction between the chain and the table surface is 0.25 s, then the maximum fraction of the length of the chain that can hang over one edge of the table is
A deuteron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to magnetic field B. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same B is
An electron with (rest mass $m_0$) moves with a speed of 0.8 c. Its mass when it moves with this speed is
A closed organ pipe (closed at one end) is excited to support the third overtone. It is found that air in the pipe has
A particle of mass m = 5 is moving with a uniform speed v = 3$\sqrt 2$ in the XOY plane along the line Y = X + 4. The magnitude of the angular momentum of the particle about the origin is
A thermos flask contains hot coffee. The flask is vigorously shaken. Then the temperature of the coffee will
A ring shaped metal is allowed to expand by heating it. The hole will
A hole is drilled along the earth's diameter and a stone is dropped into it. When the stone is at the centre of earth, it has
To use a transistor as an amplifier
A microammeter has a resistance of $100 \Omega$ and full scale range of $50 \mu A$. It can be used as a voltmeter or as a higher range ammeter provided a resistance is added to it. Pick the correct range and resistance combination (s)
Two trains move towards each other with the same speed. The speed of sound is 340 m/s. If the height of the tone of the whistle of one of them heard on the other changes to 9/8 times, then the speed of each train should be
SI unit of magnetic field is
Photoelectric work function of a metal is 1 eV. Light of wavelength $? = 3000\, \mathring{A}$ falls on it. The photo electrons come out with a maximum velocity