List of top Physics Questions

A ball of mass \( m \) moving at a speed \( v \) makes a head-on collision with an identical ball at rest. The kinetic energy at the balls after the collision is \( \frac{3}{4} \) of the original. What is the coefficient of restitution?

A stream of water flowing horizontally with the speed of 15 m/s gushes out of a tube of cross-sectional area \( 10^{-2} \, \text{m}^2 \) and hits a vertical wall nearby. What is the force exerted on the wall by the impact of water? Assuming it does not rebound.
If two simple pendulums first of bob mass \( M_1 \) and length \( l_1 \), and \( M_2 \) and \( l_2 \), Given \( M_1 = M_2 \) and \( l_1 = 2l_2 \), If the vibrational energies of both are same, then which of the following is correct?

Two coherent point sources \( S_1 \) and \( S_2 \) vibrating in phase emit light of wavelength \( \lambda \). The separation between them is \( 2\lambda \). The light is collected on a screen placed at a distance \( D \gg \lambda \) from the slit \( S_1 \) as shown. The minimum distance, so that intensity at \( P \) is equal to intensity at \( O \), is:

A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m/s, what is the recoil speed of the gun?
A man holds a rectangular card in front of and parallel to a plane mirror. In order for him to see the entire image of the card, the least mirror area needed is:
A rocket is fired from the Earth towards the Sun. At what distance from the Earth's centre, the gravitational force on the rocket is zero? Mass of the Sun = \( 2 \times 10^{30} \, \text{kg} \) and mass of the Earth = \( 6 \times 10^{24} \, \text{kg} \).
In hydrogen atom spectrum, frequency of \( 2.7 \times 10^{15} \, \text{Hz} \) of EM wave is emitted when transmission takes place from 2 to 1, the frequency emitted will be
If pressure of CO\(_2\) (real gas) in a container is given by \( P = \frac{RT}{2v-b} - \frac{a}{4v^2} \), then mass of the gas in the container is:
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:
A beam of light (\( \lambda = 600 \, \text{nm} \)) from a distant source, falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is:
The North pole of the Earth's magnetic field is at the geographical South pole. A compass is a small magnet whose North pole end is drawn in the approximate direction of
The image seen in a flat bathroom mirror is a
A U-shaped wire is dipped in a soap solution and removed. The thin soap film formed between the wire and light slider supports a weight of \( 1.5 \times 10^{-2} \, \text{N} \). The length of the slider is 30 cm. What is the surface tension of the film?
If 10% of a radioactive substance decays in every 5 years, then the percentage of the substance that will have decayed in 20 years, will be:
A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with speed 40 rev/min in a horizontal plane. What is the tension in the string and what is the maximum speed with which the stone can be whirled around, if the string can withstand a maximum tension of 200 N?

The resistance \( R \) of a conductor varies with temperature \( t \) as shown in the figure. If the variation is represented by \( R_t = R_0 \left( 1 + \alpha t + \beta t^2 \right) \), then:

A capacitor of capacitance 5 µF is connected as shown in the figure. The internal resistance of the cell is 0.5 Ω. The amount of charge on the capacitor plate is:

A liquid is poured into a vessel at rest with the hole in a wall closed by a valve. It is filled to height \( H \). The distance of the hole from the top surface is \( h \). What is the horizontal acceleration required to move the vessel so that the liquid does not come out when the valve is opened (given \( l = \) length of the base)?
A candle C sits between two parallel mirrors at a distance \( 0.2d \) from mirror 1. Here \( d \) denotes the distance between the mirrors. Multiple images of the candle appear in both mirrors. How far behind mirror 1 are the nearest three images of the candle in that mirror?

A block of mass \( m \) is in contact with the cart C as shown in the figure. The coefficient of static friction between the block and the cart is \( \mu \). The acceleration \( a \) of the cart that will prevent the block from falling satisfies:

Which of the following factors by itself will increase the frequency at which an observer hears a sound emanating from a source?

The bob of a pendulum is released from a horizontal position A as shown in the figure. If the length of the pendulum is 1.5 m, what is the speed with which the bob arrives at the lower most point B, given that it dissipated 5% of its initial energy against air resistance?

Two trains A and B of length 400 m each are moving on two parallel tracks with a uniform speed of 72 km/h in the same direction, with A ahead of speed B. The driver of B decides to overtake A and accelerates by 1 m/s². If after 50s, the guard of B just brushes past the driver of A, what was the original distance between them?

A glass prism ABC (refractive index 1.5), immersed in water (refractive index \( \frac{4}{3} \)). A ray of light is incident normally on face AB. If it is totally reflected at face AC, then