Question Paper from: JEE Main 2021 - Paper 1

A body having a specific charge of $8\mu C/g$ is resting on a frictionless plane at a distance of 10 cm from the wall (as shown in the figure). It starts moving towards the wall when a uniform electric field of 100 V/m is applied horizontally towards the wall. If the collision of the body with the wall is perfectly elastic, the time period of the motion will be _______s.

An object viewed from a near point distance of 25 cm, using a microscopic lens with magnification '6', gives an unresolved image. A resolved image is observed at an infinite distance with a total magnification double the earlier using an eyepiece along with the given lens and a tube of length 0.6 m if the focal length of the eyepiece is equal to _______cm.

When a disc slides on a smooth inclined surface from rest, the time is taken to move from A to B is t1. When
the disc performs pure rolling from rest then the time taken to move from A to B is $t_2$. If $\frac{t_2}{t_1}=\sqrt{\frac{3}{x}}$ find x.

A vehicle moving with velocity v and releasing the sound of frequency 400 Hz. Listening to the reflected sound from a wall of frequency 500 Hz. Find the velocity of vehicle v in $km/h$.

In the given arrangement spring of spring, constant 100N/m is compressed by 0.5m. The height of the arrangement is 2m. A basket is placed at a distance d such that after projection the ball will fall in the basket. If the mass of the ball is 100 gm, find the maximum value of d in meter?

For the given PV curve, The net heat is taken by the gas system in a cyclic process ..........$\pi J$

A carrier wave $V_c(t)=160\sin (2\pi \times 10^{6}t)$ volts is made to vary between $V_{max}=200V$ and $V_{min}=120V$ by a message signal $V_m(t)=A_{m}sin(2\pi \times 10^{3}t)$ volts. The peak voltage $A_m$ of the modulating signal is

Four moles of a diatomic gas are heated from $0^{o}C$ to $50^{o}C$. The heat supplied to the gas is ........R. if work done by it is zero.

A particle of mass m moving with speed v collide elastically with the end of a uniform rod of mass M and length L perpendicularly as shown in the figure. If the particle comes to rest after the collision. The ratio of masses $\left(\frac{n}{M}\right)is$\frac{1}{x}$.Thevalueof$x$$ is ...........