List of top Physics Questions

An electron projected perpendicular to a uniform magnetic field B B moves in a circle. If Bohr’s quantization is applicable, then the radius of the electronic orbit in the first excited state is:
A transparent film of refractive index 2.0 is coated on a glass slab of refractive index 1.45. What is the minimum thickness of transparent film to be coated for the maximum transmission of green light of wavelength 550 nm?
Which one of the following is the correct dimensional formula for the capacitance in F? M, L, T, and C stand for unit of mass, length, time, and charge.

A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field B B exists into the page. The bar starts to move from the vertex at time t=0 t = 0 with a constant velocity. If the induced EMF is E∝tn E \propto t^n , then the value of n n is _____. 

A small rigid spherical ball of mass M M is dropped in a long vertical tube containing glycerine. The velocity of the ball becomes constant after some time. If the density of glycerine is half of the density of the ball, then the viscous force acting on the ball will be (consider g g as acceleration due to gravity):
A body of mass 100 g is moving in a circular path of radius 2 m on a vertical plane as shown in the figure. The velocity of the body at point A is 10 m/s. The ratio of its kinetic energies at point B and C is: (Take acceleration due to gravity as 10 m/s2^2) 
body of mass 100 g is moving in a circular path
A symmetric thin biconvex lens is cut into four equal parts by two planes AB and CD as shown in the figure. If the power of the original lens is 4D, then the power of a part of the divided lens is: 
symmetric thin biconvex lens
A ball of mass 100 g is projected with velocity 20 m/s at 60∘ 60^\circ with horizontal. The decrease in kinetic energy of the ball during the motion from point of projection to highest point is:

The value of current I I in the electrical circuit as given below, when the potential at A A is equal to the potential at B B , will be _____ A. 

Two long parallel wires X and Y, separated by a distance of 6 cm, carry currents of 5 A and 4 A, respectively, in opposite directions as shown in the figure. Magnitude of the resultant magnetic field at point P at a distance of 4 cm from wire Y is 3×10−5 3 \times 10^{-5} T. The value of x x , which represents the distance of point P from wire X, is_____ \_\_\_\_\_ cm. (Take permeability of free space as μ0=4π×10−7 \mu_0 = 4\pi \times 10^{-7} SI units.) 
Two long parallel wires X and Y,
A tube of length L is shown in the figure. The radius of cross section at point (1) is 2 cm and at the point (2) is 1 cm, respectively. If the velocity of water entering at point (1) is 2 m/s, then velocity of water leaving the point (2) will be:
tube of length L
The amount of work done to break a big water drop of radius R R into 27 small drops of equal radius is 10 J. The work done required to break the same big drop into 64 small drops of equal radius will be:
A particle is executing simple harmonic motion with a time period of 2 s and amplitude 1 cm. If D D and d d are the total distance and displacement covered by the particle in 12.5 s, then the ratio Dd \frac{D}{d} is:
An electron of mass m m with an initial velocity v⃗=v0i^(v0>0) \vec{v} = v_0 \hat{i} (v_0>0) enters an electric field E⃗=−E0k^ \vec{E} = -E_0 \hat{k} . If the initial de Broglie wavelength is λ0 \lambda_0 , the value after time t t would be:
A parallel plate capacitor of area A=16 cm2 A = 16 \, \text{cm}^2 and separation between the plates 10 cm 10 \, \text{cm} , is charged by a DC current. Consider a hypothetical plane surface of area A0=3.2 cm2 A_0 = 3.2 \, \text{cm}^2 inside the capacitor and parallel to the plates. At an instant, the current through the circuit is 6A. At the same instant the displacement current through A0 A_0 is _____\_\_\_\_\_ mA.
Consider a parallel plate capacitor of area A A (of each plate) and separation d d between the plates. If E E is the electric field and ϵ0 \epsilon_0 is the permittivity of free space between the plates, then the potential energy stored in the capacitor is:
A uniform solid cylinder of mass m m and radius r r rolls along an inclined rough plane of inclination 45∘ 45^\circ . If it starts to roll from rest from the top of the plane, then the linear acceleration of the cylinder axis will be:
A parallel plate capacitor was made with two rectangular plates, each with a length of l=3 cm l = 3 \, {cm} and breadth of b=1 cm b = 1 \, {cm} . The distance between the plates is d=3 μm d = 3 \, \mu{m} . Out of the following, which are the ways to increase the capacitance by a factor of 10?
The Young's double slit interference experiment is performed using light consisting of 480 nm and 600 nm wavelengths to form interference patterns. The least number of the bright fringes of 480 nm light that are required for the first coincidence with the bright fringes formed by 600 nm light is:
An object of mass m m is projected from the origin in a vertical xy xy -plane at an angle 45∘ 45^\circ with the x-axis with an initial velocity v0 v_0 . The magnitude and direction of the angular momentum of the object with respect to the origin, when it reaches the maximum height, will be:
An alternating current is given by I=IAsin⁡ωt+IBcos⁡ωt. I = I_A \sin \omega t + I_B \cos \omega t. The r.m.s. current will be:
In a sound wave, the displacement of the air particles follows the equation y=Acos⁡(kx−ωt) y = A \cos(kx - \omega t) . What is the wave velocity?
For an experimental expression y=32.3×112527.4 y = \frac{32.3 \times 1125}{27.4} , where all the digits are significant. Then to report the value of y y , we should write:
What is the relative decrease in focal length of a lens for an increase in optical power by 0.1 D from 2.5 D? ('D' stands for dioptre).
What is the time period of a simple pendulum of length L L and acceleration due to gravity g g ?