1
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
A particle of mass m and charge q is released from rest in a uniform electric field. If there is no other force on the particle, the dependence of its speed v on the distance x travelled by it is correctly given by (graphs are schematic and not drawn to scale)
A B C D 2
JEE Main 2020 (Online) 8th January Evening Slot
+4
-1
Consider two charged metallic spheres S1 and S2 of radii R1 and R2, respectively. The electric fields E1 (on S1) and E2 (on S2) on their surfaces are such that E1/E2 = R1/R2. Then the ratio V1 (on S1) / V2 (on S2) of the electrostatic potentials on each sphere is :
A
(R1/R2)2
B
(R2/R1)
C
(R1/R2)3
D
R1/R2
3
JEE Main 2020 (Online) 8th January Morning Slot
+4
-1
In finding the electric field using Gauss Law the formula $$\left| {\overrightarrow E } \right| = {{{q_{enc}}} \over {{\varepsilon _0}\left| A \right|}}$$ is applicable. In the formula $${{\varepsilon _0}}$$ is permittivity of free space, A is the area of Gaussian surface and qenc is charge enclosed by the Gaussian surface. The equation can be used in which of the following situation?
A
Only when $$\left| {\overrightarrow E } \right|$$ = constant on the surface.
B
For any choice of Gaussian surface.
C
Only when the Gaussian surface is an equipotential surface.
D
Only when the Gaussian surface is an equipotential surface and $$\left| {\overrightarrow E } \right|$$ is constant on the surface.
4
JEE Main 2020 (Online) 8th January Morning Slot
+4
-1
Three charged particle A, B and C with charges –4q, 2q and –2q are present on the circumference of a circle of radius d. the charged particles A, C and centre O of the circle formed an equilateral triangle as shown in figure. Electric field at O along x-direction is : A
$${3{\sqrt 3 q} \over 4{\pi {\varepsilon _0}{d^2}}}$$
B
$${{\sqrt 3 q} \over 4{\pi {\varepsilon _0}{d^2}}}$$
C
$${{\sqrt 3 q} \over {\pi {\varepsilon _0}{d^2}}}$$
D
$${{2\sqrt 3 q} \over {\pi {\varepsilon _0}{d^2}}}$$
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