List of top Physics Questions

When unpolarised light is passed through crossed polaroids, then light passing through first polaroid

Five capacitors each of capacitance \(C\) are connected as shown in the figure. The ratio of equivalent capacitance between \(P\) and \(R\) and the equivalent capacitance between \(P\) and \(Q\) is

According to Abbe, in the formula for resolving power of microscope, the numerical aperture is represented by

In communication system, what is used to extend the range of a communication?

An open organ pipe and a closed organ pipe have the frequency of their first overtone identical. The ratio of length of open pipe to that of closed pipe is

A planet has radius \( \dfrac{1}{4} \)th of the radius of earth and acceleration due to gravity double than that of the earth. Then the ratio of escape velocity on the surface of the planet to that on the earth’s surface will be

A thin circular ring of mass $M$ and radius $r$ is rotating about its axis with an angular speed $\omega$. Two particles each of mass $m$ are now attached at diametrically opposite points. The angular speed of the ring will become

The figure shows two diagrams in which diode and resistance are connected. Out of the following statements which one is TRUE?

A thin light weight rod of diamagnetic substance such as silver is suspended in a uniform external magnetic field. It will align itself with its length

A particle starting from rest moves along the circumference of a circle of radius \( r \) with angular acceleration \( \alpha \). The magnitude of the average velocity, in the time it completes the small angular displacement \( \theta \), is

The unknown resistances are connected in two gaps of a metre bridge. The null point is at 20 cm from zero end. A resistance of 15 \( \Omega \) is connected in series with the smaller of the two. The null point shifts to 40 cm. The smaller resistance is

Magnetic field at the centre of a circular loop of area \( A \) is \( B \). The magnetic moment of the loop will be (\( \mu_0 \) = permeability of free space)

A lift is tied with thick iron ropes having mass \( M \). The maximum acceleration of the lift is \( a \) m/s² and maximum safe stress is \( s \) N/m². The minimum diameter of the rope is

When a certain metallic surface is illuminated with monochromatic light of wavelength $\lambda$, the stopping potential for photoelectric effect is $3V_0$. If the same surface is illuminated with light of wavelength $2\lambda$, the stopping potential is found as $V_0$. The threshold wavelength for this surface is

Two coils of wire A and B are placed mutually perpendicular as shown. When current is changed in any one coil,

In communication system, for a given block diagram of receiver, the boxes 'X' and 'Y' respectively represent

When light of wavelength \( \lambda \) is incident on photosensitive surface, photons of power \( P \) are emitted. The number of photons \( n \) emitted in \( t \) second is

In an oscillator, if $A$ is the feedback factor and $A'$ is the gain of amplifier, then sustained oscillations are obtained when

At absolute zero temperature, pure silicon behaves as

In a transverse progressive wave of amplitude \( a \), the maximum particle velocity is six times its wave velocity. The wavelength of the wave is

In the figure shown, the voltage across \( C_3 \) will be:

The threshold wavelengths for photoelectric emission from two metals A and B are 400 nm and 800 nm respectively. The ratio of their work functions \(\phi_A\) to \(\phi_B\) is

For a photocell, the work function is \(\phi\) and the stopping potential is \(V_s\). The wavelength of the incident radiation is

For a prism, \( A \) is the angle of the prism, \( \delta \) is the angle of deviation, \( \mu \) is the refractive index of the material of a prism, the refractivity of the material of a prism is

A radar of power $1\ \text{kW}$ operating at frequency $10\ \text{GHz}$ is located on a mountain top of height $500\ \text{m}$. The maximum distance upto which it can detect object located on the surface of the earth is $\left[\text{Radius of earth} = 6.4 \times 10^6\ \text{m}\right]$