JEE Main 2019 Question Paper (11-Jan-2019) (Shift-2)

Question 1

If speed (V), acceleration (A) and force (F) are considered as fundamental units, the dimension of Young's modulus will be :

Accepted Answer

$V^{-4}A^2F$

Answer

$V^{-4}A^{-2}F$

Answer

$V^{-2}A^2F^2$

Answer

$V^{-2}A^2F^{-2}$

Question 2

A particle moves from the point $(2.0\hat{i} + 4.0\hat{j})m$, at $t=0$, with an initial velocity $(5.0\hat{i} + 4.0\hat{j})\ ms^{-1}$. It is acted upon by a constant force which produces a constant acceleration $(4.0\hat{i} + 4.0\hat{j})\ ms^{-2}$.What is the distance of the particle from the origin at time $2\ s$?

Accepted Answer

$20\sqrt{2}\ m$

Answer

$15\ m$

Answer

$10\sqrt{2}\ m$

Answer

$5\ m$

Question 3

The magnitude of torque on a particle of mass $1\ kg$ is $2.5\ Nm$ about the origin. If the force acting on it is $1\ N$, and the distance of the particle from the origin is $5\ m$, the angle between the force and the position vector is (in radians) :

Accepted Answer

$\frac{\pi}{6}$

Answer

$\frac{\pi}{3}$

Answer

$\frac{\pi}{4}$

Answer

$\frac{\pi}{8}$

Question 4

A particle of mass $m$ is moving in a straight line with momentum $p$. Starting at time $t=0$, a force $F = kt$ acts in the same direction on the moving particle during time interval $T$ so that its momentum changes from $p$ to $3p$. Here $k$ is a constant. The value of $T$ is:

Accepted Answer

$2\sqrt{\frac{P}{k}}$

Answer

$\sqrt{\frac{2p}{k}}$

Answer

$2\sqrt{\frac{k}{P}}$

Answer

$\sqrt{\frac{2k}{P}}$

Question 5

A particle of mass $m$ and charge $q$ is in an electric and magnetic field given by$\vec{E}=2\hat{i}+3\hat{j}$; $\vec{B}=4\hat{j}+6\hat{k}$.The charged particle is shifted from the origin to the point $P(x=1;\ y=1)$ along a straight path. The magnitude of the total work done is :

Accepted Answer

$5q$

Answer

$(2.5)q$

Answer

$(0.15)q$

Answer

$(0.35)q$