List of top Physics Questions

When a proton is released from rest in a room, it starts with an initial acceleration $a_0$ towards west. When it is projected towards north with a speed $v_0$ it moves with an initial acceleration 3$a_0$ toward west. The electric and magnetic fields in the room

A piece of iron is heated in a flame. It first becomes dull red then becomes reddish yellow and finally turn to white hot. The correct explanation for the above observation is possible by using

The wettability of a surface by a liquid depends primarily on

A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when

An explosion breaks a rock into three parts in a horizontal plane. Two of them go off at right angles to each other. The first part of mass 1 kg moves with a speed of 12 $ms^{-1}$ and the second part of mass 2 kg moves with 8 $ms^{-1}$ speed. If the third part flies off with 4 $ms^{-1}$ speed, then its mass is

A plano-convex lens fits exactly into a plano- concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices, $μ_1$ and $μ_2$ and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is

The wavelength $λ_e$ of an electron and $λ_p$ of a photon of same energy E are related by

The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied?

A body of mass w taken from the earth's surface to the height equal to twice the radius (R) of the earth. The change in potential energy of body will be

A wire of resistance 4Ω is stretched to twice its original length. The resistance of stretched wire would be

For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behind the comes is 20 D. Using this information, the distance between the retina and the comea-eye lens can be estimated to be

Infinite number of bodies, each of mass 2 kg are situated on x-axis at distance 1 m, 2 m, 4 m, 8 m respectively, from the origin. The resulting gravitational potential due to this system at the origin will be

Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is

The molar specific heats of an ideal gas at constant pressure and volume are denoted by $C_p$ and $C_V$ respectively. If $ γ = \frac{C_P}{C_v}$ and R is the universal gas constant, then $C_V$ is equal to

In a n-type semiconductor, which of the following statement is true?

A source of unknown frequency gives 4 beats/s, when sounded with a source of known frequency 250 Hz. The second harmonic of the source of unknown frequency gives five beats per second, when sounded with a source of frequency 513 Hz. The unknown frequency is

The output (X) of the logic circuit shown in figure will be

In an experiment four quantities a, b, c and d are measured with percentage error 1%, 2%, 3% and 4% respectively. Quantity P is calculated as follows: P= $\frac{a^3 b^2}{cd}$ % error in P is

A certain mass of Hydrogen is changed to Helium by the process of fusion. The mass defect in fusion reaction is 0.02866 u. The energy liberated per u is (given 1 u=931 MeV)

The half life of a radioactive isotope 'X' is 20 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be

For photoelectric emission from certain metal the cut-off frequency is v. If radiation of frequency 2v impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass)

A bar magnet of length I and magnetic dipole moment M is bent in the form of an arc as shown in figure. The new magnetic dipole moment will be

A small object of uniform density rolls up a curved surface with an initial velocity . It reaches up to a maximum height of $\frac{3v^2}{4g}$with respect to the initial position. The object is

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of Cp/Cv for the gas is

A fluid is in streamline flow across a horizontal pipe of variable area of cross section. For this which of the following statements is correct?