List of top Physics Questions asked in JEE Main

The position of center of mass of three masses 2 kg, 3 kg and 15 kg placed with respect to mid point ($p$) of normal bisector, as shown in the figure is _________

The rain drop of mass $1$ g, starts with zero velocity from a height of $1$ km. It hits the ground with a speed of $5$ m/s. The work done by the unknown resistive force is —————— J.
(take $g = 10$ m/s$^2$)

The density $\rho$ of a uniform cylinder is determined by measuring its mass $m$, length $l$ and diameter $d$. The measured values of $m, l$ and $d$ are $97.42 \pm 0.02$ g, $8.35 \pm 0.05$ mm and $20.20 \pm 0.02$ mm, respectively. Calculated percentage fractional error in $\rho$ is

A lift of mass $1600\text{ kg}$ is supported by thick iron wire. If the maximum stress which the wire can withstand is $4 \times 10^8\text{ N/m}^2$ and its radius is $4\text{ mm}$, then maximum acceleration the lift can take is ______ $\text{m/s}^2$. (take $g = 10\text{ m/s}^2$ and $\pi = 3.14$)

The potential energy of a particle changes with distance $x$ from a fixed origin as $V = \frac{A\sqrt{x}}{x + B}$, where $A$ and $B$ are constant with appropriate dimensions. The dimensions of $AB$ are

Potential energy of a particle is given as $ u = \dfrac{A\sqrt{x}}{B+x} $. Find the dimensions of $A$ and $B$.

On a metal surface if light of wavelength $\lambda$ falls stopping potential for emitted photoelectron is $3V_0$ and if light of wavelength $2\lambda$ falls stopping potential is $V_0$. Find threshold wavelength :-

Two strings with lengths $l_1$ and $l_2$, and Young's moduli $Y_1$ and $Y_2$ are elongated under two weights as shown. Find the ratio $\Delta l_1 / \Delta l_2$.
Case (1): String has Young's modulus $Y$, length $l$, cross–sectional area $A$ and a mass $m$ is attached.
Case (2): String has Young's modulus $2Y$, length $0.5l$, cross–sectional area $A$ and a mass $3m$ is attached.

Two cars $A$ and $B$ are moving on a road with speeds $100\,\text{km/h}$ and $80\,\text{km/h}$ respectively. A stone is thrown from car $B$ with speed $V$ km/h relative to it. The stone hits car $A$ with speed $5\,\text{m/s}$ relative to car $A$ (ignore gravity). Find $V$.

Consider a ring of radius $R$ which rotates about a horizontal axis as shown (axis is tangent to the ring). Find the time period of small oscillations.

List-I presents some physical quantities and List-II presents their dimensions. Match the two lists appropriately.

For the given capacitor circuit, find out the equivalent capacitance between A and B:

A dipole is kept in an electric field $ \vec{E}_1 = E_0 \hat{i} $. It oscillates with frequency $ f_1 $. A new electric field $ \vec{E}_2 = 2E_0 \hat{j} + 2E_0 \hat{k} $ is superimposed. The dipole now oscillates in the direction of $ \vec{E}_{\text{net}} $ with frequency $ f_2 $. Find the percentage change in frequency.

Match the given quantities according to their dimensions:

Two rods and two blocks are connected as shown in the figure. Find out the ratio of extension in the rods (Assuming standard configuration where upper rod supports both blocks and lower rod supports one):
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Why do only a few $ \alpha $-particles rebound from the gold nucleus in Rutherford's experiment?
S1: Size of gold nucleus is very small compared to the gold atom.
S2: Impact parameter of $ \alpha $-particles is very small.
S3: Nuclear charge of $ \mathrm{He^{2+}} $ particles is very small compared to gold.
S4: Very few $ \alpha $-particles undergo head-on collision.
Then correct statements are:

$ \vec{B} = B_0 \sin (\omega t - kx) \hat{j} $ is the magnetic field of an EM wave. Then its electric field is:

A rod of length L is heated from temperature $ T_1 $ to $ T_2 $. Let $ T_2 - T_1 = \Delta T $ and the expansion of the rod be $ \Delta L_1 $. The rod is further heated from $ T_2 $ to $ T_3 $ such that $ T_1 + T_3 = 2T_2 $. Find the expansion of the rod $ \Delta L_2 $:

A toy gun fires bullets in every possible direction. It is found that the bullet lands at a maximum horizontal distance of 6.4 m from the gun. Find the speed of projection ($ g = 10 \, \mathrm{m/s^2} $).

Two cars A & B are moving on a road with speed 100 km/hr and 80 km/hr. A stone is thrown from car B with speed $ V $ km/hr relative to it. Stone hits the car A with speed 5 m/s with respect to car A (ignore gravity). The value of $ V $ is: [All given velocities are in the same direction]

At what height does gravitational acceleration become 1/9th of gravity at the surface of a planet, if the radius of the planet is $ R $?

A particle is projected from the ground whose $ x, y $-coordinates vary with time according to the equations $ x = 24t $ and $ y = 43.6t - 4.9t^2 $. Find the initial angle $ \theta $ made by the velocity vector $ \vec{v} $ with the $ x $-axis.

Electron and proton are accelerated with the same potential to achieve de-Broglie wavelengths of $ \lambda_1 $ and $ \lambda_2 $. Given $ m_p = 1849 \, m_e $, find the ratio $ \lambda_1/\lambda_2 $:

Assertion: For a diode in reverse bias, current is independent of applied voltage before breakdown and it increases drastically just after breakdown.
Reason: Before breakdown only majority charge carriers flow.

Point P is at $ r = 5 \, \mathrm{cm} $ distance from the centers of two bar magnets, each of magnetic moment $ 3\sqrt{5} \, \mathrm{A \! \cdot \! m^2} $. Find the magnetic field at P (assuming magnets are placed such that P is on their axial/equatorial lines).