List of top Physics Questions

Half life of radioactive element is 12.5 Hour and its quantity is 256 gm. After how much time its quantity will remain 1 gm : -

A particle is thrown vertically upward. Its velocity at half of the height is 10 m/s. Then the maximum height attained by it (g = 10 m/s^2 )

Copper and silicon is cooled from 300 K to 60 K, the specific resistance

If specific resistance of a potentiometer wire is $10^{-7}\, \Omega m$ and current flow through it is 0.1 amp., cross-sectional area of wire is $10^{-6}\, m^2$ then potential gradient will be

With what velocity should a particle be projected so that its height becomes equal to radius of earth?

A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is

The dimensions of Planck constant equals to that of

A black body has wavelength $\lambda_m$ corresponding to maximum energy at 2000 K. Its wavelength corresponding to maximum energy at 3000 K will be:

An electron having mass m and kinetic energy E enter in uniform magnetic field B perpendicularly, then its frequency will be

In the figure shown a block of weight 10 N is resting on a horizontal surface (figure). The coefficient of static friction between the block and surface is force of 3.5 N will keep the block in uniform motion, once it has been set in motion. A horizontal force of 3 N is applied to the block then:

A sine wave has an amplitude A and wavelength $\lambda$ . Let V be the wave velocity and maximum velocity of a particle in the medium. Then

The magnetic fields at two points on the axis of a circular coil at distance of 0.05 m and 0.2 m from the centre are in the ratio 8 :1 . The radius of the coil is

If the energy of a hydrogen atom in nth orbit is $E_n$, then energy in the nth orbit of a singly ionized helium atom will be

A point source of light is placed 4 m below the surface of water of refractive index is 5/3. The minimum diameter of a disc which should be placed over the source on the surface of water to cut-off all light coming out of water is:

A cylindrical rod having temperature T1 and T2 at its end. The rate of flow of heat Q1 cal/sec. If all the linear dimension are doubled keeping temperature remain const. then rate of flow of heat Q2 will be

Two waves having equation $x_1=a \sin(\omega t-kx+\phi_1),$ $ x_2=a \sin (\omega t-kx +\phi_2)$ If in the resultant wave the frequency and amplitude remain equal to amplitude of superimposing waves, the phase difference between them is

Energy is released in nuclear fission is due to

X(n, α) 7/3Li , then X will be

Biological importance of ozone layer is

A dipole of dipole moment $ \overrightarrow{ p} $ is placed in uniform electric field $ \overrightarrow{ E}$ then torque acting on it is given by

The equation of a wae is represented by $y=10^{-4} \sin \Bigg(100t -\frac{x}{10}\Bigg)m, $ then the velocity of wave will be

A scientist says that the efficiency of his heat engine which work at source temperature $127^{\circ } C $ and sink temperature $27^{\circ} C $ is $26\% ,$ then

A cricketer catches a ball of mass 150 gm in 0.1 sec moving with speed 20 m/s, then he experiences force of

A 1 kg stationary bomb is exploded in three parts having mass $1 : 1 : 3$ respectively. Part having same mass move in perpendicular direction with velocity 30 m/s, then the velocity of bigger part will be

A balloon rises from ground with an acceleration of $1.25\, m s^{-2}$. After $8s$ a stone is released from balloon. The stone will