List of top Physics Questions

A screw gauge has least count of 0.01 mm and there are 50 divisions in its circular scale. The pitch of the screw gauge is:

Light with an average flux of $20\,\Omega/cm^2$ falls on a non-reflecting surface at normal incidence having surface area $20\,cm^2$. The energy received by the surface during time span of $1\,minute$ is :

A spherical conductor of radius 10 cm has a charge of \(3.2 \times 10^{-7} C\) distributed uniformly. What is the magnitude of electric field at a point \(15\,cm\) from the centre of the sphere?
\((\frac {1}{4\pi \epsilon_o} = 9 \times 10^9 Nm^2/C^2)\)

The increase in the width of the depletion region in a p-n junction diode is due to :

An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is $1.227 \times 10^{-2}nm$, the potential difference is :

An iron rod of susceptibility 599 is subjected to a magnetising field of 1200 A $m^{-1}$. The permeability of the material of the rod is : $(\mu_o = 4\pi \times 10^{-7} T\,m\,A^{-1})$

Dimensions of stress are:

For transistor action, which of the following statements is correct ?

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?

For the logic circuit shown, the truth table is :

Which of the following graph represents the variation of resistivity $(\rho)$ with temperature (T) for copper ?

A wheel with $20$ metallic spokes each $1\, m$ long is rotated with a speed of $120\, rpm$ in a plane perpendicular to a magnetic field of $0.4\, G$. The induced emf between the axle and rim of the wheel will be, $(1 G = 10^{-4}\, T)$

A wire of length L, area of cross section A is hanging from a fixed support. The length of the wire changes to \(L_1\) when mass M is suspended from its free end. The expression for Young’s modulus is:

A wire of length $L$ metre carrying a current of $I$ ampere is bent in the form of a circle. Its magnetic moment is,

Three identical spheres, each of mass $M$, are placed at the corners of a right angle triangle with mutually perpendicular sides equal to $2\,m$ (see figure). Taking the point of intersection of the two mutually perpendicular sides as the origin, find the position vector of centre of mass

Two bodies of mass $4\,kg$ and $6\,kg$ are tied to the ends of a massless string. The string passes over a pulley which is frictionless (see figure). The acceleration of the system in terms of acceleration due to gravity (g) is :

The energy required to break one bond in DNA is $10^{-20}J $. This value in eV is nearly

The total energy of an electron in the $n^{th}$ stationary orbit of the hydrogen atom can be obtained by

The average thermal energy for a mono-atomic gasis : (kBis Boltzmann constant and T, absolute temperature)

In Young’s double slit experiment, if the separation between coherent sources is halved and the distance of the screen from the coherent sources is doubled, then the fringe width becomes :

A charged particle having drift velocity of \(7.5×10^{−4} m s^{−1} \) in an electric field of  has a mobility in  \(m^2 V^{−1} s^{−1}\) of :

The quantities of heat required to raise the temperature of two solid copper spheres of radii \(r _1\) and \(r_2\)  \((r_1=1.5 r_2 )\) through \(1 K\) are in the ratio

A capillary tube of radius r is immersed in waterand water rises in it to a height h. The mass of the water in the capillary is 5 g. Another capillary tube of radius 2r is immersed in water. The massof water that will rise in this tube is

Two coherent sources of light interfere and produce fringe pattern on a screen. For central maximum, the phase difference between the two waves will be

The electric potential \(V\) at any point \((x,y,z)\) in space is given by \(V=4xz^2\) volt, where \(x,y,z\) are all in metre. The electric field at that point \((1\text{ m},0,2\text{ m})\) in \(\text{V m}^{-1}\) is