List of top Physics Questions asked in JEE Main

The de Broglie wavelength associated with an electron accelerated through a potential difference V is \( \lambda_e \) and the de Broglie wavelength associated with a proton accelerated through the same potential difference is \( \lambda_p \). If their corresponding masses are \( m_e \) and \( m_p \), respectively, then the ratio of their de Broglie wavelengths \( \frac{\lambda_e}{\lambda_p} \) is:

In Rutherford's alpha-particle scattering experiment, only a few alpha particles rebound back because:
A. The size of gold nucleus is very small as compared to the size of gold atom.
B. Alpha particle and gold nucleus have equal charge.
C. The impact parameter is minimum for a few alpha particles.
D. A few alpha particles have very high kinetic energy.
E. Only a few alpha particles undergo head-on collision with the nuclei.
Choose the correct answer from the options given below:

An unpolarized light of certain intensity passes through a combination of two polarizers whose transmission axes are at \(30^\circ\) and \(90^\circ\), respectively, with respect to the horizontal axis. A third polarizer with its transmission axis at \(60^\circ\) with the horizontal axis is placed between the two existing polarizers. The ratio of the output intensities with and without the third polarizer is:

A convex lens is made from glass material having refractive index of 1.4 with same radius of curvature on both sides. The ratio of its focal length and radius of curvature is:

A magnetic field vector in an electromagnetic wave is represented by
$\vec{B} = B_0 \sin \left( 2\pi \nu t - \frac{2\pi x}{\lambda} \right) \hat{j}$. Its associated electric field vector is _______.

A solenoid has a core made of material with relative permeability 400. The magnetic field produced in the interior of solenoid is 1.0 T. The magnetic intensity in SI units is $\alpha \times 10^5$. The value of $\alpha$ is ________.
(Free space permeability $\mu_0 = 4\pi \times 10^{-7}$ SI units.)

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In electrostatics, a conductor does not store any net charge inside.
Reason R: Inside the capacitor (with no dielectric medium), the free charge carriers, if placed between the plates of capacitor, experience force and drift.
Choose the correct answer from the options given below

From the circuit given below, the capacitance between terminals A and B shown in the circuit is _______ $\mu\text{F}$.
(take $C_1 = C_2 = C_3 = 1 \mu\text{F}$ and $C_4 = 2 \mu\text{F}$.)

A rigid dipole undergoes a simple harmonic motion about its centre in the presence of an electric field $\vec{E}_1 = E_0 \hat{x}$. If another electric field $\vec{E}_2 = 2E_0 (\hat{y} + \hat{z})$ is introduced to the system, what will be the percentage change in the frequency of the oscillation (approximate)?

A uniform disc of radius $R$ and mass $M$ is free to oscillate about the axis A as shown in the figure. For small oscillations the time period is _______.
(g is acceleration due to gravity)

The temperature of a metal strip having coefficient of linear expansion $\alpha$ is increased from $T_1$ to $T_2$ resulting in increase of its length by $\Delta L_1$. The temperature is further increased from $T_2$ to $T_3$ such that the increase in its length is $\Delta L_2$.
Given $T_3 + T_1 = 2T_2$ and $T_2 - T_1 = \Delta T$, the value of $\Delta L_2$ is ________.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: If the average kinetic energy of $H_2$ and $O_2$ molecules, kept in two different sized containers are same, then their temperatures will be same.
Reason R: The r.m.s. speed of $H_2$ and $O_2$ molecules are same at same temperature.
Choose the correct answer from the options given below

A water spray gun is attached to a hose of cross sectional area $30 \text{ cm}^2$. The gun comprises of 10 perforations each of cross sectional area of $15 \text{ mm}^2$. If the water flows in the hose with the speed of 50 cm/s, calculate the speed at which the water flows out from each perforation. (Neglect any edge effects)

A metal string A is suspended from a rigid support and its free end is attached to a block of mass M. Second block having mass 2M is suspended at the bottom of the first block using a string B. The area of cross sections of strings A and B are same. The ratio of lengths of strings of A to B is 2 and the ratio of their Young's moduli ($Y_A / Y_B$) is 0.5. The ratio of elongations in A to B is _______.

The height in terms of radius of the earth ($R$), at which the acceleration due to gravity becomes $g/9$, where $g$ is acceleration due to gravity on earth's surface, is

At $t = 0$, a body of mass 100 g starts moving under the influence of a force $(5\hat{i} + 10\hat{j})$ N. After 2 s its position is $(2x\hat{i} + 5y\hat{j})$ m. The ratio $x : y$ is______.

Two cars A and B are moving in the same direction along a straight line with speeds 100 km/h and 80 km/h, respectively such that car A is moving ahead of car B. A person in car B throws a stone with a speed $v$ so that it hits the car A with a speed of 5 m/s. The value of $v$ is ______ km/h.

Match the LIST-I with LIST-II

Choose the correct answer from the options given below:

Moment of inertia about an axis \( AB \) for a rod of mass 40 kg and length 3 m is same as that of a solid sphere of mass 10 kg and radius \( R \) about an axis parallel to \( AB \) axis with separation of 3 m as shown in the figure below. The value of \( R \) is given as \( \sqrt{\frac{\alpha}{2}} \). The value of \( \alpha \) is _______.

If sunlight is focused on a paper using a convex lens, it starts burning the paper in the shortest time when the lens is kept at 30 cm above the paper. If the radius of curvature of the lens is 60 cm, then the refractive index of the lens material is \( \frac{\alpha}{10} \). The value of \( \alpha \) is _______.

5 moles of unknown gas is heated at constant volume from 10°C to 20°C. The molar specific heat of this gas at constant pressure \( c_p = 8 \) cal/mol·°C and \( R = 8.36 \) J/mol·°C. The change in the internal energy of the gas is _______ calorie.}

Using Bohr's model, calculate the ratio of the magnetic fields generated due to the motion of the electrons in the 2nd and 4th orbits of a hydrogen atom.

In a Young's double slit experiment, the intensity at some point on the screen is found to be \( \frac{3}{4} \) times of the maximum of the interference pattern. The path difference between the interfering waves at this point is \( \frac{\lambda}{x} \), where \( \lambda \) is the wavelength of the incident light. The value of \( x \) is _______.}

The equation of motion of a particle is given by \( x = a \sin \left( 50t + \frac{\pi}{3} \right) \, \text{cm}. \) The particle will come to rest at time \( t_1 \) and it will have zero acceleration at time \( t_2 \). The \( t_1 \) and \( t_2 \) respectively are _______.