List of top Physics Questions

A metal wire of density ‘ρ’ floats on water surface horizontally. If it is NOT to sink in water, then maximum radius of wire is (T = surface tension of water, g = gravitational acceleration)

A photon of energy ‘E’ ejects photoelectrons from a metal surface whose work function is W₀. If this electron enters into uniform magnetic field of induction ‘B’ in a direction perpendicular to field and describes a circular path of radius‘r’, then radius is given by

A liquid drop having surface energy ‘E’ is spread into 216 droplets of the same size. The final surface energy of the droplets is __.

An equation of a simple harmonic progressive wave is given by y = A sin (100πt-3x).The distance between two particles having a phase difference of $\frac {π}{3}$ in metre is

Two satellites A and B rotate round a planet’s orbit having radius 4R and R respectively. If the speed of satellite A is 3 V then speed of satellite B is

Two thin lenses have a combined power of +9D. When they are separated by a distance of 20 cm, then their equivalent power becomes +27/5 D. Their individual power (in dioptre) is

In a p-type semiconductor

A diffraction pattern is obtained by making blue light incident on a narrow slit. If blue light is replaced by red light then

In metre bridge experiment, null point is obtained at 20 cm from left end of the wire, when resistance X is balanced against another resistance Y (X < Y). To balance a resistance 4 X against Y, the new position of the null point from the same end will be

The work done by a force on body of mass 5 kg to accelerate it in the direction of force from rest to 20 m/s² in 10 second is

What is intensive property?

A light wave of wavelength ‘λ’ is incident on a slit of width ‘d’. The resulting diffraction pattern is observed on a screen at a distance ‘D’.If linear width of the principal maximum is equal to the width of the slit, then the distance D is

What is change in internal energy if a system gains xJ of heat and yJ work is done on it?

Air column in two identical tubes is vibrating. Tube A has one end closed and tube B has both ends open. Neglecting end correction, the ratio of the fundamental frequency of air column in tube A to that in tube B is

For a particle performing S.H.M. the equation $ \frac{d^2x}{dt^2} + \alpha x = 0 $. Then the time period of the motion will be:

Consider the following statements about interference of light.
A – When crest of one wave coincides with crest of another wave at a point, this point is a point of destructive interference.
B – Two coherent sources emit wave of same frequency with constant phase difference.
Choose the correct option from the following.

A satellite of mass ‘m’ is revolving around the earth of mass ‘M’ in an orbit of radius ‘r’. The angular momentum of the satellite about the centre of orbit will be

If kinetic energy of a body is increased by 300\%, then the percentage change in momentum will be

A copper and a steel wire of same diameter are connected end to end. A deforming force $ F_1 $ is applied to the wire which causes an elongation of 1 cm. The two wires will have

During $ \alpha $-decay, the atomic mass of parent nuclei is

For a CE transistor amplifier, the audio signal voltage across the collector resistance of $ 4 \, \text{k}\Omega $ is 5V. If the current amplification factor of the transistor is 100 and the base resistance is $ 2 \, \text{k}\Omega $, then the input signal voltage is

A point object is placed on the optic axis of a convex lens of focal length $ f $ at a distance of $ 2f $ to the left of it. The diameter of the lens is $ d $. An eye is placed at a distance of $ 3f $ to the right of the lens and a distance $ h $ below the optic axis. The maximum value of $ h $ to see the image is

If the Earth were to spin faster, acceleration due to gravity at the poles

During the phenomenon of resonance, the amplitude of oscillation becomes large. The variation of g with angular velocity $ \omega $ is given by \[ g' = g - R\omega^2 \] If Earth were to spin faster, that is, angular velocity increases, then except at poles, the weight of bodies will decrease at all places.

If a heat engine is filled at temperature $ 27^\circ C $ and heat of 100 kcal is taken from the source at temperature $ 677^\circ C $, work done (in J) is