List of top Physics Questions

An $\alpha -$ particle moves in a circular path of radius $0.83\, cm$ in the presence of a magnetic field of $0.25\, Wb/m^2. $ The de Broglie wavelength associated with the particle will be (Take $h = 6.63 ? 10^{-34} J\, s$, $e =1.6 ?10^{-19}C$)

The height at which the weight of a body becomes $1 / 16^{\text {th }}$, its weight on the surface of earth (radius R), is

A particle has initial velocity $ ( 2 \vec{i} + 3 \vec{j})$ and acceleartion ($ 0 . 3 \vec{i} + 0 . 2 \vec{j})$ The magnitude of velocity after 10 seconds will be

A geostationary satellite is orbiting the earth at a height of $5\,R$ above that surface of the earth, $R$ being the radius of the earth. The time period of another satellite in hours at a height of $2\,R$ from the surface of the earth is

A train moving at a speed of $220\,ms^{-1}$ towards a stationary object, emits a sound of frequency $1000\, Hz$. Some of the sound reaching the object gets reflected back to the train as echo. The frequency of the echo as detected by the driver of the train is (Speed of sound in air is $330\,ms^{-1}$)

A milli voltmeter of $25$ milli volt range is to be converted into an ammeter of $25$ ampere range. The value (in ohm) of necessary shunt will be

A spherical planet has a mass $M_p$ and diameter $D_p$. A particle of mass $m$ falling freely near the surface of this planet will experience an acceleration due to gravity, equal to

To get the maximum flight, a ball must be thrown as

An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be ($m$ is the mass of the electron, $R$, Rydberg constant and $h$ Planck's constant)

A magnetic needle suspended parallel to a magnetic field requires $\sqrt 3 \,J$ of work to turn it through $60^\circ.$ The torque needed to maintain the needle in this position will be

Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state.
The ratio of the wavelengths \(\lambda_1 : \lambda_2\) emitted in the two cases is:

An electron and a proton, both having the same kinetic energy, enter a region of uniform magnetic field, in a plane perpendicular to the field. If their masses are denoted by $m_{e}$ and $m_{p}$ respectively, then the ratio of the radii (electron to proton) of their circular orbits is

Which of the following is the correct Kirchhoff's loop rule?

What is the resonance frequency of a driven $LCR$ oscillator?

A cheetah, weighing $150 \,kg$, chases a deer, weighing $30 \, kg$, in a straight path. The speed of the cheetah is $20 \,m / s$ and that of the deer is $25 m / s$. The approximate speed of the centre of mass of the pair is

A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It.

A circular platform is mounted on a frictionless vertical axle. Its radius R = 2 m and its moment of inertia about the axle is $ 200\, kg\, m^2 $. It is initially at rest. A 50 kg man stands on the edge of the platform and begins to walk along the edge at the speed of $ 1 \,ms^{-1} $ relative to the ground. Time taken by the man to complete one revolution is

The potential energy of a particle in a force field is $ U=\frac{A}{r^2}-\frac{B}{r}$ where A and B are positive constants and r is the distance of particle from the centre of the field. For stable equilibrium, the distance of the particle is

In a slide callipers, $(m + 1)$ number of vernier divisions is equal to m number of smallest main scale divisions. If d unit is the magnitude of the smallest main scale division, then the magnitude of the vernier constant is

Charge passing through a conductor of cross-section area $A=0.3 \,m ^{2}$ is given by $q=3 t^{2}+5 t+2$ in coulomb, where $t$ is in second. What is the value of drift velocity at $t=2 s ?$ (Given, $\left.n=2 \times 10^{25} / \,m ^{3}\right)$

$A$ and $B$ are two metals with threshold frequencies $1.8 \times 10^{14}\, Hz$ and $2.2 \times 10^{4}\, Hz$ Two identical photons of energy $0.825 \,eV$ each are incident on them. Then photoelectrons are emitted by (Take $\left.h=6.6 \times 10^{-34} \,J - s \right)$

A direct $X$ -ray photograph of the intenstines is not generally taken by radiologists because

A rod of length $10\, cm$ lies along the principal axis of a concave mirror of focal length $10\, cm$ in such a way that its end closer to the pole is $20\, cm$ away from the mirror. The length of the image is

Two capacitors of capacities $1 \, \mu F$ and $C \, \mu F$ are connected in series and the combination is charged to a potential difference of $120 \,V$. If the charge on the combination is $80 \, \mu C$, the energy stored in the capacitor of capacity $C$ in $\mu J$ is

If voltage across a bulb rated $220 \,V$- $100\, W$ drops by $2.5\%$ of its rated value, the percentage of the rated value by which the power would decrease is