List of top Physics Questions

Two cars are moving towards each other at the speed of $ 50\, \text{m/s} $. If one of the cars blows a horn at a frequency of $ 250\, \text{Hz} $, what is the wavelength of the sound perceived by the driver of the other car?
(Speed of sound in air = $ 350\, \text{m/s} $)

A body of mass 10 kg is projected at an angle of 45° with the horizontal. The trajectory of the body is observed to pass through a point (20, 10). If T is the time of flight, then its momentum vector, at time t = T/√2, is _________.
[Take g = 10m/s²]

A particle is moving along x-axis with velocity $ v = \frac{1}{1 + \beta t} $. At time $ t = 0 $, the particle is at $ x = 0 $. The displacement as a function of time is:

A current $ I $ flows along the length of an infinitely long, straight, thin-walled pipe. Then:

When you walk through a metal detector carrying a metal object in your pocket, it raises an alarm. This phenomenon works on:

A convex lense of focal length 'l' is placed somewhere in between an object and a screen. The distance between the object and the screen is 'x'. If the numerical value of the magnification produced by the lens is 'm'. Then the focal lenght of the lens is

A needle is lying at the bottom of a water tank of height $ 12\, \text{cm} $. The apparent depth of the needle measured by a microscope is $ 9\, \text{cm} $. If the water is replaced by a liquid of refractive index 1.5 (same height), the distance through which the microscope has to be moved to focus the needle again is:

Match List I with List II.

List I	List II
A.	Torque	I.	Nms^–1
B.	Stress	II.	Jkg^–1
C.	Latent Heat	III.	Nm
D.	Power	IV	Nm^–2

Choose the correct answer from the options given below

A juggler throws balls vertically upwards with same initial velocity in air. When the first ball reaches its highest position, he throws the next ball. Assuming the juggler throws n balls per second, the maximum height the balls can reach is

A freshly prepared radioactive source of half life 2 hours 30 minutes emits radiation which is 64 times the permissible safe level. The minimum time, after which it would be possible to work safely with source, will be _______ hours.

The frequencies at which the current amplitude in an LCR series circuit becomes $\frac{1}{2}$ times its maximum value, are 212 rad s^–1 and 232 rad s^–1. The resistance value in the Question: the circuit is R = 5 Ω. The self-inductance in the circuit is _____ mH.

A circuit element X when connected to an a.c. supply of peak voltage 100 V gives a peak current of 5 A which is in phase with the voltage. A second element Y when connected to the same a.c. supply also gives the same value of peak current which lags behind the voltage by $\frac{π}{2}$. If X and Y are connected in series to the same supply, what will be the rms value of the current in ampere?

A liquid of density 750 kgm^–3 flows smoothly through a horizontal pipe that tapers in
cross-sectional area from A₁ = 1.2 × 10^–2m² to
$A_2=\frac{A_1}{2}$
. The pressure difference between the wide and narrow sections of the pipe is 4500 Pa. The rate of flow of liquid is _____ × 10^–3 m³s^–1.

From a circular disc of radius $ R $, a square is cut out with a radius as its diagonal. The centre of mass of the remaining portion is at a distance (from the centre)

If the potential at A is greater than the potential at B, then the equivalent resistance of the circuit across AB is

In the following circuit, the equivalent resistance between X and Y is ...... $ \Omega $:

In a resonance column, the first and second resonance are obtained at depths 24 cm and 78 cm. The third resonance will be obtained at what depth?

For an insulator, the forbidden energy gap is:

In the circuit shown in the figure, the AC source gives a voltage $ V = 20\cos(2000t) $. Neglecting source resistance, the voltmeter and ammeter readings will be:

The recoil speed of a hydrogen atom after it goes from $ n = 5 $ state to $ n = 1 $ state will be:

Zener breakdown occurs in a p − n junction having p and n both:

A stone of mass $ m $, tied to a string is being whirled in a vertical circle with a uniform speed. The tension in the string is:

Angular momentum of the particle rotating with a central force is constant due to

The escape velocity of a body depends upon mass as:

Potential energy as a function of $r$ is given by $ U = \frac{A}{r^{10}} - \frac{B}{r^5} $, where $r$ is the interatomic distance, $A$ and $B$ are positive constants. The equilibrium distance between the two atoms will be: