List of top Physics Questions asked in JEE Main

Find number of photons emitted per second by a light source of wavelength $663\,\text{nm}$ at power $6\,\text{mW}$. If $h = 6.63 \times 10^{-34}\,\text{Js}$ is $N \times 10^{15}$, then find $N$.

Block of mass $3\,\text{kg}$ is connected to a flywheel of mass $3\,\text{kg}$ and radius $5\,\text{m}$ through a massless string wrapped around the flywheel. Find kinetic energy (in J) of flywheel when block descends by $3\,\text{m}$.

Find time taken by the block to reach the bottom.

Mass number of a nucleus is $\alpha$ and its radius is $R_\alpha$. Radius of another nucleus of mass number $\beta$ is $R_\beta$. If $\beta = 8\alpha$, then find $\dfrac{R_\alpha}{R_\beta}$.

For a particle moving in x-direction according to the relation $x = 4t^3 - 3t$, consider the following statements:

[(a)] At $t = 0.866$, $x = 0$
[(b)] Direction of velocity of particle remains same
[(c)] Direction of velocity of particle changes at $x = -1$
[(d)] Direction of velocity of particle changes at $x = 0.5\,\text{m}$
[(e)] Acceleration is non-negative
Correct statements are:

If percentage increase in Young's modulus $Y$ is $1%$, percentage increase in density of material is $0.5%$ and longitudinal wave traveling in a metallic bar has wave velocity of $400\,\text{m/s}$, then find final velocity of the wave.

A current is flowing along the surface of a long solid cylinder of radius $R$. Select the correct statement(s):

[(A)] Magnetic field ($B$) is minimum along the axis of cylinder
[(B)] Magnetic field ($B$) is minimum at the surface of cylinder
[(C)] Magnetic field ($B$) is maximum at the surface of cylinder
[(D)] Magnetic field ($B$) is maximum along the axis of cylinder
[(E)] Magnetic field ($B$) is same all over the cross section of cylinder

In the given circuit, energy stored in the inductor is $16\,\text{J}$ and power dissipated in resistance is $32\,\text{W}$. Find the value of $\dfrac{X_L}{R}$.

A light ray incident on a slab of refractive index $ \frac{3}{2} $. If the wavelength of the refracted ray is 520 nm, find the wavelength of the incident ray.

Ice is heated from $-20^\circ C$ to $200^\circ C$. Which of the following temperature (T) vs heat (Q) graph is correct ?

If nothing is kept between jaws, zero of Vernier scale lies right of 0 cm of main scale and $4^{th}$ line of Vernier scale matches perfectly with any line of main scale. An object is kept between jaws and zero of Vernier scale crosses $15^{th}$ division of main scale and $5^{th}$ division of Vernier scale exactly matches with any line of main scale. (Least count = 0.1 mm and 1 MSD = 1mm). Find dimension of object :

A particle is falling under gravity. Air resistance on particle is F = $-$kv. Find correct option :

Two wires of cross sectional area $1 \text{ cm}^2$ and $2 \text{ cm}^2$ and lengths 20 cm and 30 cm are connected to the same load. If their extensions are same, find the ratio of their Young's modulus :

10kg ice at $-10^\circ C$ & 100kg water at $25^\circ C$ are mixed together. Find final temperature. (Given $S_{ice} = \frac{1}{2}$ cal/g$^\circ C$, $L_{fusion} = 80$cal/g and $S_{water} = 1$cal/g$^\circ C$)

In the system of two discs and a rod of mass 600 g each, a torque of magnitude $43 \times 10^5$ dyne-cm is applied along the axis of rotation as shown in figure. Find the approx angular acceleration about given axis :

Find external force F so that block can move on inclined plane with constant velocity.

As shown in the figure, radius of gyration about the axis shown in $\sqrt{n}$ cm for a solid sphere. Find 'n'.

For given nuclear reactions:
\[ ^4_2\mathrm{He} + ^1_0\mathrm{n} \rightarrow ^3_2\mathrm{He} + 20\,\text{MeV} \] \[ ^4_2\mathrm{He} + ^1_0\mathrm{n} \rightarrow ^4_2\mathrm{He} - 0.9\,\text{MeV} \] $X_3$ represents stability of $^3_2\mathrm{He}$, $X_4$ represents stability of $^4_2\mathrm{He}$ and $X_5$ represents stability of $^5_2\mathrm{He}$. Compare the stabilities.

When rod becomes horizontal find its angular velocity. It is pivoted at point A as shown.

Find magnetic field at midpoint O. Rings have radius $R$ and direction of current is in opposite sense.

A solid cylinder of radius $\dfrac{R}{3}$ and length $\dfrac{L}{2}$ is removed along the central axis. Find ratio of initial moment of inertia and moment of inertia of removed cylinder.

Velocity of particle varies with position as shown in figure. Find the correct variation of acceleration with position.

Resistance of each side is $R$. Find equivalent resistance between two opposite points as shown in the figure.

A cylindrical object of density $600\,\text{kg/m}^3$ and height $8$ cm is floating in a liquid of density $900\,\text{kg/m}^3$. Find height of cylinder inside liquid.

In case of meter bridge experiment balance length for $2\Omega$ and $3\Omega$ is $\ell$ and for $x\Omega$ and $3\Omega$ is $(\ell + 10)$ cm. Find $x$.