List of top Physics Questions asked in JEE Main

The galvanometer deflection, when key \(K_1\) is closed but \(K_2\) is open, equals \(\theta_0\) (see figure). On closing \(K_2\) also and adjusting \(R_2\) to \(5\,\Omega\), the deflection in galvanometer becomes \(\frac{\theta_0}{5}\). The resistance of the galvanometer is, then, given by [Neglect the internal resistance of battery] :

The least count of the main scale of a screw gauge is 1 mm. The minimum number of divisions on its circular scale required to measure 5 \(\mu\)m diameter of a wire is :

There is a uniform spherically symmetric surface charge density at a distance \(R_0\) from the origin. The charge distribution is initially at rest and starts expanding because of mutual repulsion. The figure that represents best the speed \(V(R(t))\) of the distribution as a function of its instantaneous radius \(R(t)\) is :

A particle of mass m and charge q is in an electric and magnetic field given by
\(\vec{E} = 2\hat{i} + 3\hat{j};\ \vec{B} = 4\hat{j} + 6\hat{k}\).
The charged particle is shifted from the origin to the point P(x = 1; y = 1) along a straight path. The magnitude of the total work done is :

A particle of mass m is moving in a straight line with momentum p. Starting at time t = 0, a force F = kt acts in the same direction on the moving particle during time interval T so that its momentum changes from p to 3p. Here k is a constant. The value of T is :

A pendulum is executing simple harmonic motion and its maximum kinetic energy is \(K_1\). If the length of the pendulum is doubled and it performs simple harmonic motion with the same amplitude as in the first case, its maximum kinetic energy is \(K_2\). Then :

A monochromatic light is incident at a certain angle on an equilateral triangular prism and suffers minimum deviation. If the refractive index of the material of the prism is \(\sqrt{3}\), then the angle of incidence is:

In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm. The decrease in the stopping potential is close to: ( \( \frac{hc}{e} = 1240 \) nm eV)

A galvanometer having a resistance of \(20\ \Omega\) and 30 divisions on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:

In a double-slit experiment, green light (5303 Å) falls on a double slit having a separation of \(19.44\ \mu\mathrm{m}\) and a width of \(4.05\ \mu\mathrm{m}\). The number of bright fringes between the first and the second diffraction minima is :

Two rods A and B of identical dimensions are at temperature \( 30^\circ\mathrm{C} \). If A is heated upto \( 180^\circ\mathrm{C} \) and B upto \( T^\circ\mathrm{C} \), then the new lengths are the same. If the ratio of the coefficients of linear expansion of A and B is 4 : 3, then the value of T is

An electric field of 1000 V/m is applied to an electric dipole at angle of \( 45^\circ \). The value of electric dipole moment is \( 10^{-29} \) C.m. What is the potential energy of the electric dipole?

A particle moves from the point \( (2.0\hat{i} + 4.0\hat{j}) \) m, at t = 0, with an initial velocity \( (5.0\hat{i} + 4.0\hat{j}) \) \( \mathrm{ms^{-1}} \). It is acted upon by a constant force which produces a constant acceleration \( (4.0\hat{i} + 4.0\hat{j}) \) \( \mathrm{ms^{-2}} \). What is the distance of the particle from the origin at time 2 s?

The region between \( y = 0 \) and \( y = d \) contains a magnetic field \( \overrightarrow{B} = B\hat{z} \). A particle of mass m and charge q enters the region with a velocity \( \overrightarrow{v} = v\hat{i} \). If \( d = \frac{mv}{2qB} \), the acceleration of the charged particle at the point of its emergence at the other side is :

In the circuit shown, the potential difference between A and B is :

The circuit shown below contains two ideal diodes, each with a forward resistance of \( 50\ \Omega \). If the battery voltage is 6 V, the current through the \( 100\ \Omega \) resistance (in Amperes) is :

A gas mixture consists of 3 moles of oxygen and 5 moles of argon at temperature T. considering only translational and rotational modes, the total internal energy of the system is :

In an experiment, electrons are accelerated, from rest, by applying a voltage of 500 V. Calculate the radius of the path if a magnetic field 100 mT is then applied. [Charge of the electron = \(1.6 \times 10^{-19}\) C Mass of the electron = \(9.1 \times 10^{-31}\) kg]

A body is projected at t = 0 with a velocity 10 ms\(^{-1}\) at an angle of \(60^\circ\) with the horizontal. The radius of curvature of its trajectory at t = 1s is R. neglecting air resistance and taking acceleration due to gravity g = 10 ms\(^{-2}\), the value of R is :

In a Young's double slit experiment, the path difference, at a certain point on the screen, between two interfering waves is \(\frac{1}{8}\) th of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to :

A liquid of density \(\rho\) is coming out of a hose pipe of radius \(a\) with horizontal speed \(v\) and hits a mesh. 50% of the liquid passes through the mesh unaffected. 25% looses all of its momentum and 25% comes back with the same speed. The resultant pressure on the mesh will be :

The force of interaction between two atoms is given by \(F = \alpha\beta\exp\left(-\frac{x^2}{\alpha kt}\right)\); where \(x\) is the distance, \(k\) is the Boltzmann constant and \(T\) is temperature and \(\alpha\) and \(\beta\) are two constants. The dimension of \(\beta\) is :

An electromagnetic wave of intensity 50 Wm\(^{-2}\) enters in a medium of refractive index 'n' without any loss. The ratio of the magnitudes of electric, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively, given by:

An object is at a distance of 20 m from a convex lens of focal length 0.3 m. The lens forms an image of the object. If the object moves away from the lens at a speed of 5 m/s, the speed and direction of the image will be :

If the de Broglie wavelength of an electron is equal to the \(10^{-3}\) times the wavelength of a photon of frequency \(6 \times 10^{14}\) Hz, then the speed of electron is equal to : (Speed of light = \(3 \times 10^{8}\) m/s, Planck's constant = \(6.63 \times 10^{-34}\) J.s, Mass of electron = \(9.1 \times 10^{-31}\) kg)