List of top Physics Questions asked in JEE Main

The temperature, at which the root mean square velocity of hydrogen molecules equals their escape velocity from the earth, is closest to :
[Boltzmann Constant \(k_B = 1.38\times10^{-23}\ \mathrm{J/K}\)
Avogadro Number \(N_A = 6.02\times10^{26}\ \mathrm{/kg}\)
Radius of Earth : \(6.4\times10^{6}\ \mathrm{m}\)
Gravitational acceleration on Earth = \(10\ \mathrm{ms^{-2}}\)]

A rocket has to be launched from earth in such a way that it never returns. If E is the minimum energy delivered by the rocket launcher, what should be the minimum energy that the launcher should have if the same rocket is to be launched from the surface of the moon ? Assume that the density of the earth and the moon are equal and that the earth's volume is 64 times the volume of the moon :-

A positive point charge is released from rest at a distance \(r_0\) from a positive line charge with uniform density. The speed (\(v\)) of the point charge, as a function of instantaneous distance \(r\) from line charge, is proportional to :-

A nucleus A, with a finite de-broglie wavelength \(\lambda_A\), undergoes spontaneous fission into two nuclei B and C of equal mass. B flies in the same direction as that of A, while C flies in the opposite direction with a velocity equal to half of that of B. The de-Broglie wavelengths \(\lambda_B\) and \(\lambda_C\) of B and C are respectively :

A body of mass \(m_1\) moving with an unknown velocity of \(v_1\hat{i}\), undergoes a collinear collision with a body of mass \(m_2\) moving with a velocity \(v_2\hat{i}\). After collision, \(m_1\) and \(m_2\) move with velocities of \(v_3\hat{i}\) and \(v_4\hat{i}\), respectively. If \(m_2 = 0.5\,m_1\) and \(v_3 = 0.5\,v_1\), then \(v_1\) is :-

Young's moduli of two wires A and B are in the ratio 7 : 4. Wire A is 2 m long and has radius R. Wire B is 1.5 m long and has radius 2 mm. If the two wires stretch by the same length for a given load, then the value of R is close to :-

A parallel plate capacitor has \(1\ \mu\)F capacitance. One of its two plates is given \(+2\ \mu\)C charge and the other plate, \(+4\ \mu\)C charge. The potential difference developed across the capacitor is:-

Two magnetic dipoles X and Y are placed at a separation d, with their axes perpendicular to each other. The dipole moment of Y is twice that of X. A particle of charge q is passing, through their midpoint P, at angle \(\theta = 45^\circ\) with the horizontal line, as shown in figure. What would be the magnitude of force on the particle at that instant ?
(d is much larger than the dimensions of the dipole)

In the figure shown, what is the current (in Ampere) drawn from the battery ?
You are given: \(R_1 = 15\ \Omega\), \(R_2 = 10\ \Omega\), \(R_3 = 20\ \Omega\), \(R_4 = 5\ \Omega\), \(R_5 = 25\ \Omega\), \(R_6 = 30\ \Omega\), \(E = 15\) V

The given diagram shows four processes i.e., isochoric, isobaric, isothermal and adiabatic. The correct assignment of the processes, in the same order is given by :-

A particle moves in one dimension from rest under the influence of a force that varies with the distance travelled by the particle as shown in the figure. The kinetic energy of the particle after it has travelled 3m is :

In SI units, the dimensions of \(\sqrt{\dfrac{\in_0}{\mu_0}}\) is :

The wavelength of the carrier waves in a modern optical fiber communication network is close to :

For the circuit shown, with R₁ = 1.0W, R₂ = 2.0 W, E₁ = 2 V and E₂ = E₃ = 4 V, the potential difference between the points 'a' and 'b' is approximately (in V):

A 200 \(\Omega\) resistor has a certain color code. If one replaces the red color by green in the code, the new resistance will be :

Ship A is sailing towards north-east with velocity \(\vec{v} = 30\hat{i} + 50\hat{j}\) km/hr where \(\hat{i}\) points east and \(\hat{j}\), north. Ship B is at a distance of 80 km east and 150 km north of Ship A and is sailing towards west at 10 km/hr. A will be at minimum distance from B in :

Water from a pipe is coming at a rate of 100 litres per minute. If the radius of the pipe is 5 cm, the Reynolds number for the flow is of the order of : (density of water = 1000 kg/m³, coefficient of viscosity of water = 1mPas)

Radiation coming from transitions \(n = 2\) to \(n = 1\) of hydrogen atoms fall on \(\mathrm{He^+}\) ions in \(n = 1\) and \(n = 2\) states. The possible transition of helium ions as they absorb energy from the radiation is :

In figure, the optical fiber is \(l\) = 2m long and has a diameter of d = 20 \(\mu\)m. If a ray of light is incident on one end of the fiber at angle \(\theta_1\) = 40°, the number of reflection it makes before emerging from the other end is close to: (refractive index of fibre is 1.31 and sin 40° = 0.64)

An upright object is placed at a distance of 40 cm in front of a convergent lens of focal length 20 cm. A convergent mirror of focal length 10 cm is placed at a distance of 60 cm on the other side of the lens. The position and size of the final image will be :

The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit.

The current \(I_Z\) through the Zener is :

Four particles A, B, C and D with masses \(m_A = m\), \(m_B = 2m\), \(m_C = 3m\) and \(m_D = 4m\) are at the corners of a square. They have accelerations of equal magnitude with directions as shown. The acceleration of the centre of mass of the particles is :

A wire of length \(2L\), is made by joining two wires A and B of same length but different radii \(r\) and \(2r\) and made of the same material. It is vibrating at a frequency such that the joint of the two wires forms a node. If the number of antinodes in wire A is \(p\) and that in B is \(q\) then the ratio \(p : q\) is :

The bob of a simple pendulum has mass 2g and a charge of \(5.0\ \mu\mathrm{C}\). It is at rest in a uniform horizontal electric field of intensity 2000 V/m. At equilibrium, the angle that the pendulum makes with the vertical is : (take \(g = 10\ \mathrm{m/s^2}\))

Two particles move at right angle to each other. Their de-Broglie wavelengths are \(\lambda_1\) and \(\lambda_2\) respectively. The particles suffer perfectly inelastic collision. The de-Broglie wavelength \(\lambda_2\) of the final particle, is given by :