List of top Physics Questions

If the energy released per fission of a $^{235}U$ nucleus is 200 MeV, the energy released in the fission of 0.1 kg of $^{235}U$ in kilowatt-hour is:

The semiconductor used for fabrication of visible LEDs must at least have a band gap of:

A body thrown vertically upwards reaches a maximum height $ H $. The ratio of the velocities of the body at heights $ \frac{3H}{4} $ and $ \frac{8H}{9} $ from the ground is:

The equation of projectile motion is given by $ y = 3x - 0.8x^2 $. The time of flight of the projectile is (Acceleration due to gravity $ g = 10 $ m/s²):

A 100 kg gun fires a ball of 1 kg horizontally from a cliff of height 500 m. It falls on the ground at a distance of 400 m from the bottom of the cliff. The recoil velocity of the gun is (Acceleration due to gravity $ g = 10 $ ms$^{-2}$):

A satellite moving around the Earth in a circular orbit has kinetic energy $ E $. Then, the minimum amount of energy to be added so that it escapes from the Earth is:

A metal ball of mass 100 g at $ 20^\circ C $ is dropped in 200 ml of water at $ 80^\circ C $. If the resultant temperature is $ 70^\circ C $, then the ratio of specific heat of the metal to that of water is:

An ideal gas is taken around ABCA as shown in the P-V diagram. The work done during a cycle is:

The ratio of kinetic energy of a diatomic gas molecule at a high temperature to that of NTP is:

The vibrations of four air columns are shown below. The ratio of frequencies is:

A neutral ammonia (NH$_3$) molecule in its vapour state has an electric dipole moment of magnitude $ 5 \times 10^{-30} $ C·m. How far apart are the molecule's centers of positive and negative charge?

Eight capacitors each of capacity $ 2 $ µF are arranged as shown in the figure. The effective capacitance between A and B is:

Two identical cells gave the same current through an external resistance of $ 2 $$\omega$ regardless of whether the cells are grouped in series or parallel. The internal resistance of the cells is:

Three rings, each with equal radius $ r $, are placed mutually perpendicular to each other and each having centre at the origin of the coordinate system. If $ I $ is the current passing through each ring, the magnetic field value at the common centre is:

A 50 Hz AC circuit has a 10 mH inductor and a 2 $\omega$ resistor in series. The value of capacitance to be placed in series in the circuit to make the circuit power factor unity is:

The structure of solids is investigated by using:

The surface of a metal is first illuminated with a light of wavelength 300 nm and later illuminated by another light of wavelength 500 nm. It is observed that the ratio of maximum velocities of photoelectrons in two cases is 3. The work function of the metal value is close to:

The ratio of the minimum wavelength of the Balmer series to the maximum wavelength in the Brackett series in the hydrogen spectrum is:

The half-life period of a radioactive element A is 62 years. It decays into another stable element B. An archaeologist found a sample in which A and B are in 1 : 15 ratio. The age of the sample is:

A man of mass 70 kg jumps to a height of 0.8 m from the ground, then the momentum transferred by the ground to the man is
(g = 10 m/s$^{-2}$):

Three particles of each mass $ m $ are kept at the three vertices of an equilateral triangle of side $ 1 $. The moment of inertia of the system of the particles about any side of the triangle is:

If the work done $W$, length $L$ and time $T$ are considered as the fundamental quantities, the dimensional formula for mass is:

The relation between the force (F in newton) acting on a particle executing simple harmonic motion and the displacement of the particle (y in metre) is given by: \[ 500F + \pi^2 y = 0 \] If the mass of the particle is 2 g, the time period of oscillation of the particle is:

The RMS value of the electric field of an electromagnetic wave emitted by a source is $ 660 $ N/C. The average energy density of the electromagnetic wave is:

The focal length of double concave lens having refractive index 1.5 kept in air with two spherical surfaces of radii $ R_1 = 20 \, \text{cm} $ and $ R_2 = 80 \, \text{cm} $ is