List of top Physics Questions

Atomic mass number of an element is 232 and its atomic number is 90. The end products of this radioactive element is an isotope of lead (Atomic mass 208 and atomic number 82). The number of $\alpha\,and\,\beta$-particle emitted is

Atomic weight of Boron is 10.81 and it has two isotopes $_5B^{10}$ and $ _5B^{11}$ Then the ratio of $_5B^{10} :_5B^{11}$ in nature would be

At what temperature will the speed of sound in air be $3$ times its value at $0\,^?C$?

At what temperature is the rms velocity of hydrogen molecule equal to that of an oxygen molecule at $47\,^{\circ}C$?

At zero degree kelvin a piece of Germanium

At what temperature, hydrogen molecules will escape from the earth's surface? (Take mass of hydrogen molecule $=0.34\times10^{-26} kg,$ Boltzmann constant $-1.38\times10^{-23} J K^{-1},$ Radius of earth $=6.4\times10^{6} m$ and acceleration due to gravity $=9.8 ms^{-2}$ )

At what height above the surface of earth the value of acceleration due to gravity would be half of its value on the surface of earth? (Radius of the earth is 6400 km)

At the maximum height of a projectile, the velocity and acceleration are

At the maximum height of a body thrown vertically up

At room temperature, the rms speed of the molecules of a certain diatomic gas is found to be $1933\, m \,s^{-1}$. The gas is $(R = 8.3\, J\, mol^{-1}\, K^{-1}$ )

At resonance frequency the impedance in series $LCR$ circuit is

At constant temperature, the volume of a gas is to be decreased by 4%. The pressure must be increased by

At any instant, a rolling body may be considered to be in pure rotation about an axis through the point of contact. This axis is translating forward with speed

At any instant the ratio of the amount of radioactive substance is 2 : 1. If their half lives be respectively 12 and 16 hours, then after two days, the ratio of the substances is

At a given instant, there are $25\%$ undecayed radioactive nuclei in a sample. After $10$ seconds the number of undecayed nuclei reduces to $12.5\%$, the mean life of the nuclei is

At $10^{\circ}$ C the value of the density of a fixed mass of an ideal gas divided by its pressure is $x$ . At $110^{\circ}$C this ratio is:

Assume the earth's orbit around the sun as circular and the distance between their centers as 'D' mass of the earth is 'M' and its radius is 'R' If earth has an angular velocity $'\omega_0'$ with respect to its center and $'\omega'$ with respect to the center of the sun, the total kinetic energy of the earth is:

Assume that the acceleration due to gravity on the surface of the moon is 0.2 times the acceleration due to gravity on the surface of the earth, If R,. is the maximum range of a projectile on the earth's surface, what is the maximum range on the surface of the moon for the same velocity of projection

Assume a bulb of efficiency $2.5\%$ as a point source. The peak values of electric and magnetic fields produced by the radiation coming from a $100\, W$ bulb at a distance of $3\, m$ is respectively

: Young's modulus for a perfectly plastic body is zero. : For a perfectly plastic body restoring force is zero

:Zener diode is used to obtain voltage regulation. :When Zener diode is operated in reverse bias, after a certain voltage (breakdown voltage) the current suddenly increases.

: Zener diode works on principle of breakdown voltage. :Current increases suddenly after breakdown voltage.

Work done by friction over a closed path is not zero and no potential energy can be associated with friction. Every force encountered in mechanics have an associated potential energy.

: When a light wave travels from a rarer to a denser medium, its speed decreases. The decrease in speed imply a reduction in energy carried by the light wave. : The energy of a wave is inversely proportional to velocity of wave.

When distance between two bodies is doubled and also mass of each body is doubled, gravitational force between them remains the same. According to Newton?? law of gravitation, force is directly proportional to product of the mass of bodies and inversely proportional to the square of the distance between them.