List of top Physics Questions

If the coefficient of static friction between the tyres and road is $0.5$, what is the shortest distance in which an automobile can be stopped when travelling at $72\,km/h$?

Half-lives of two radioactive substances A and B are respectively 20 min and 40 min. Initially the samples of A and B have equal number of nuclei. After 80 min the ratio of remaining number of A and B nuclei is

Compressional wave pulses are sent to the bottom of sea from a ship and the echo is heard after $2 s$. If bulk modulus of elasticity of water is $2 \times 10^{9} \,N / m ^{2}$ and mean temperature is $4^{\circ} C$, the depth of the sea will be

Alternating current is transmitted to take places

The magnetic moment has dimensions of

A particle moving with a uniform acceleration travels $24\, m$ and $64\,m$ in the first two consecutive interval of $4s$ each. Its initial velocity will be

A gas bubble formed from an explosion under water oscillates with a period $T$ proportional to $P^{a} d^{b} E^{c}$, where $P$ is pressure, $d$ is the density of water and $E$ is the total energy of explosion. The value of $a, b, c$ are

If the radius of earth of $R$ then the height h at which the value of $g$ becomes one-fourth, will be

A body is projected at such angle that the horizontal range is three times the greatest height. The angle of projection is

A meter stick is held vertically with one end on the floor and is then allowed to fall. Assuming that the end on the floor the stick does not slip, the velocity of the other end when it hits the floor, will be

Two spheres of masses $m$ and $M$ are situated in air and the gravitational force between them is $F$. The space around the masses in now filled with a liquid of specific density $3.$ The gravitational force will now be :

The potential energy of a simple harmonic oscillator when the particle is half way to its end point is - (where, $E$ is the total energy)

The acceleration due to gravity becomes $\left(\frac{g}{2}\right)$ where (g = acceleration due to gravity on the surface of the earth) at a height equal to

The acceleration due to gravity on the planet $A$ is $9$ times the acceleration due to gravity on planet $B. A$ man jumps to a height of $2\, m$ on the surface of $A.$ What is the height of jump by the same person on the planet $B$.

An equiconvex lens is cut into two halves along (i) $XOX'$ and (ii) $YOY'$ as shown in the figure. Let ${f, f', f'' }$be the focal lengths of the complete lens, of each half in case (i), and of each half in case (ii), respectively.

Choose the correct statement from the following

A wire is suspended by one end. At the other end a weight equivalent to 20 N force is applied. If the increase in length is 1 mm, the increase in the energy of the wire will be

A spring balance and a physical balance are kept in a lift. In these balances equal masses are placed. lf now the lift starts moving upwards with constant acceleration, then

A sample of radioactive element has a mass of $10\, g$ at an instant $t = 0$. The approximate mass of this element in the sample after two mean lives is

A particle is thrown vertically upwards. Its velocity at half of the height is $ 10\, ms^{ - 1} $ . Then the maximum height attained by it is (Take $g = 10\,ms^{ -2} $ )

Barrier potential of $a p-n$ junction diode does not depend on

A man weighs $80\, kg$. He stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of $5 \,ms^{-2}$ What would be the reading on the scale? ($g = 10\, ms^{-2})$

An observer moves towards a stationary source of sound with a speed $1 / 5\, th$ of the speed of sound. The wavelength and frequency of the source emitted are $\lambda$ and $f$ respectively. The apparent frequency and wavelength recorded by the observer are respectively

The kinetic energy of $1 \,g$ molecule of a gas, at normal temperature and pressure is $( R = 8.31 \,J \, mol^{-1} \, K^{-1} )$

Consider a compound slab consisting of two different materials having equal thickness and thermal conductivities $K$ and $2K$ respectively. The equivalent thermal conductivity of the slab is