List of top Physics Questions

A magnetic field $B=B_0 \widehat{j}$ exists in the region a < x < 2 a and $B=-B_0 \widehat{j}$ in the region 2a < x < 3a, where $B_0$ is a positive constant. A positive point charge moving with a velocity$v-v_0 \widehat{i} $ where $v_0$ is a positive constant, enters the magnetic field at x = a. The trajectory of the charge in this region can be like
The largest wavelength in the ultraviolet region of the hydrogen spectrum is $122 \,nm$. The smallest wavelength in the infrared region of the hydrogen spectrum (to the nearest integer) is
Vector which is perpendicular to $a \, \cos \theta \hat i + b \, \sin \, \theta \hat j$ is
Fission of nuclei is possible because the binding energy per nucleon in them
An electron moves in a circular orbit with a uniform speed $ v $ . It produces a magnetic field $B$ at the centre of the circle. The radius of the circle is proportional to
The nuclei of which one of the following pairs of nuclei are isotones?
A drum of radius $R$ and mass $M$, rolls down without slipping along an inclined plane of angle $ \theta$ The frictional force
Imagine a new planet having the same density as that of earth but it is $3$ times bigger than the earth in size. If the acceleration due to gravity on the surface of earth is g and that on the surface of the new planet is g, then
The primary and secondary coils of a transformer have $50$ and $1500$ turns respectively. If the magnetic flux $\phi$ linked with the primary coil is given by $\phi=\phi_{0}+4 t$, where $\phi$ is in weber, $t$ is time in second and $\phi_{0}$ is a constant, the output voltage across the secondary coil is
Two identical charges repel each other with a force equal to $10\, mgwt$ when they are $0.6\, m$ apart in air.$( g = 10 ms^{-2} )$ The value of each charge is
The volume of a nucleus is directly proportional to .........
The maximum particle velocity in a wavemotion is half the wave velocity. Then the amplitude of the wave is equal to
The current passing through the ideal ammeter in the circuit given below is
A ray of light is travelling from glass to air. (Refractive index of glass = $1.5$) The angle of incidence is $50^\circ$. The deviation of the ray is
A radioactive substance contains $10,000$ nuclei and its half life period is $20$ days. The number of nuclei present at the end of $10$ days is
A ray of light is incident normally on one face of a right angled isosceles prism. It then grazes the hypotenuse. The refractive index of the material of the prism is
A wheel has angular acceleration of $3.0 \,rad/sec^{-2}$ and an initial angular speed of $2.00\, rad\,s^{-1}$. In a time of $2\, s$ it has rotated through an angle (in radian) of
A uniform rod $A B$ of length $\ell$ and mass $m$ is free to rotate about point $A .$ The rod is released from rest in the horizontal position. Given that the moment of inertia of the rod about $A$ is $\frac{m \ell^{2}}{3}$, the initial angular acceleration of the rod will be:-
If $B_{H}=\frac{1}{\sqrt{3}} B_{V}$, find angle of dip. (where symbols have their usual meanings)
what is the Q-value of the reaction $p+{ }^{7} Li \rightarrow{ }^{4} He +{ }^{4} He$ The atomic masses of ${ }^{1} H ,{ }^{4} He$ and ${ }^{7} Li$ are $1.007825\, u , 4.002603\,u$ and $7.016004\, u$ respectively
A can is taken out from a refrigerator at $0^{\circ} C$. The atmospheric temperature is $25^{\circ}C$. If $t_1$ is the time taken to heat from $0^{\circ} C$ to $5^{\circ} C$ and $t_2$ is the time taken from $10^{\circ} C$ to $15^{\circ}C$, then :
At what point of a projectile motion, acceleration and velocity are perpendicular to each other ?
Initially two gas samples $1$ and $2$ are at the same condition. The volume of the two are halved, one isothermally and the other adiabatically. What is the relation between the final pressure $P_1$ and $ P_2$ ?
A rocket of mass $1000\, kg$ is exhaust gases at a rate of $4\, kg/s$ with a velocity $3000\, m/s$. The thrust developed on the rocket is :
Energy gas between valence band and conduction band of a semiconductor is :