List of top Physics Questions

The objective of a microscope is immersed in a liquid of refractive index 1.5. If the semi-vertical angle of the cone of light rays of wavelength 600 nm from the object that fall on the objective is \(30^\circ\), then the minimum resolvable distance for this microscope is:

The ratio of the speeds of light in a prism P and in vacuum is \(1:\sqrt3\) and the angle of minimum deviation is \(60^\circ\). In another prism Q of same angle of prism, if the angle of minimum deviation is \(30^\circ\), then the refractive index of the material of prism Q is:

A point object is at rest on the principal axis at a distance of 20 cm from a concave mirror of radius of curvature 30 cm. Under the action of a horizontal force, the object moves away from the mirror along the axis and reaches a distance of 40 cm from the mirror in a time of 3 s. The acceleration of the image is:

At constant pressure, if equal amounts of heat are supplied to a monoatomic gas and a rigid diatomic gas, then the ratio of the changes in the internal energies of the monoatomic and diatomic gases is:

The emissivities of the surfaces of two spheres P and Q of radii \(2R\) and \(3R\) are 0.35 and 0.7 respectively. The ratio of the powers radiated by the spheres P and Q is \(9:8\). If the wavelength at which sphere P emits radiations of maximum intensity is \(4000\ \text{\AA}\), then the wavelength at which sphere Q emits radiations of maximum intensity is:

A vessel of volume 2000 cc is filled with 5 moles of an ideal gas at a temperature of \(127^\circ C\). The total kinetic energy of the gas in the vessel is:

If sound waves of frequency 169 Hz are incident horizontally on a perfectly rigid vertical wall, then the shortest distance from the wall at which the air particle will have maximum amplitude of vibration is:

If the excess pressure inside a spherical mercury drop is \(1240\,Nm^{-2}\), then the radius of the mercury drop is:

If the Poisson's ratio of the material of a wire is 0.35, then the ratio of the longitudinal and volume strains of the wire is:

A tank contains 140 cm height of water at the bottom and an oil of density \(900\,kg\,m^{-3}\) to a height of 200 cm above water. If the liquids are immiscible, then the initial velocity of efflux of water through a small opening at the bottom of the tank is:

A circular disc of radius \(15\,cm\) and mass \(10\,kg\) is suspended by a wire attached to its centre. When the wire is twisted by rotating the disc and released, the period of torsional oscillations of the disc is \(1.5\,s\). The torsional spring constant of the wire is nearly:

A body is thrown vertically upwards from the surface of the earth with a velocity \(K\) times the orbital velocity of a satellite near the surface of the earth. If the maximum height reached by the body is 200% more than the radius of the earth, then the value of \(K^{2}\) is:

A uniform thin circular disc of mass \(M\) and radius \(R\) is shown in the figure. The moment of inertia of the shaded region about the diameter AB of the disc is:

Two brass spheres approaching each other with the same speed collide head-on elastically. After collision, if one of the spheres of radius \(R\) comes to rest, then the radius of the other sphere is:

The shift (in metre) in centre of mass when the largest possible equilateral triangular plate is removed from a uniform square plate of side \(2\,m\) with one of their sides coinciding is:

A tank of height \(5\,m\) is completely filled with water and a cube of side \(1\,cm\) and density \(1.5\,g\,cm^{-3}\) is placed at the bottom of the tank. The work to be done to lift the cube at the bottom to a height of \(15\,m\) above the surface of water is:

A body of mass \(M\) is suspended from the lower end of an aeroplane accelerating horizontally. If the rope can withstand a maximum tension \(T\), then the maximum acceleration of the aeroplane is:

A flag on a boat at rest is fluttering in the south-east direction when the wind is blowing at a speed of \(72\) kmph. If the boat starts moving towards south with a speed of \(36\sqrt2\) kmph, then the direction of the flag on the boat is:

Statement-I: When two quantities are multiplied, the relative error in the result is the sum of the relative errors in the quantities.
Statement-II: When two quantities are divided, the relative error in the result is the difference of the relative errors in the quantities.

Law of conservation of mass was regarded as another basic conservation law of nature until the advent of:

Two trains A and B are moving in the same direction with velocities \(V_A\) and \(V_B\) respectively and a third train C is moving in opposite direction. If velocity of C with respect to B is twice the velocity of A with respect to B, then velocity of A with respect to C is:

The work function of Mg, Cu, Ag, Li are \(3.7, 4.8, 4.3, 2.5\,\text{eV}\) respectively. A wavelength of \(300\,\text{nm}\) light is shined on them. The metals which undergo photoelectric effect are

The half-life of a certain radio isotope is \(4\) minutes. The number of radioactive nuclei at a given instant is \(10^6\). Then the number of radioactive nuclei left \(2\) minutes later would be

The energy of an electron in Bohr's hydrogen atom is \(-3.4\,eV\). The angular momentum of the electron is

Light of wavelength \(1000\AA\) incidents on a metal surface of work function \(6\,eV\). The maximum kinetic energy of photoelectrons is