EASY
JEE Main
IMPORTANT
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A cube of side a has point charges +Q located at each of its vertices except at the origin where the charge is -Q. The electric field at the centre of cube is:

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Important Questions on Electrostatics

EASY
JEE Main
IMPORTANT
Two equal capacitors are first connected in series and then in parallel. The ratio of the equivalent capacities in the two cases will be:
HARD
JEE Main
IMPORTANT
Two electrons each are fixed at a distance 2d. A third charge proton placed at the midpoint is displaced slightly by a distance xxd perpendicular to the line joining the two fixed charges. Proton will execute simple harmonic motion having angular frequency:
(m= mass of charged particle)
EASY
JEE Main
IMPORTANT

A point charge of +12 μC is at a distance 6 cm vertically above the centre of a square of side 12 cm as shown in figure. The magnitude of the electric flux through the square will be _________ ×103 N m2 C-1.(Write the value to the nearest integer)

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HARD
JEE Main
IMPORTANT
The electric field in a region is given by E=35E0i^+45E0j^ N C-1. The ratio of flux of reported field through the rectangular surface of area 0.2 m2 (parallel to y-z plane) to that of the surface of area 0.3 m2 (parallel to x-z plane) is a:b=a:2, where a=? [Here i^, j^ and k^ are unit vectors along x, y and z -axes respectively]
MEDIUM
JEE Main
IMPORTANT
512 identical drops of mercury are charged to a potential of 2 V each. The drops are joined to form a single drop. The potential of this drop is V in Volt.
MEDIUM
JEE Main
IMPORTANT
An electron with kinetic energy K1 enters between parallel plates of a capacitor at an angle α with the plates. It leaves the plates at angle β with kinetic energy K2. Then the ratio of kinetic energies K1:K2 will be :
EASY
JEE Main
IMPORTANT

A charge q is placed at one corner of a cube as shown in figure. The flux of electrostatic field E through the shaded area is:

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EASY
JEE Main
IMPORTANT

Two small spheres each of mass 10 mg are suspended from a point by threads 0.5 m long. They are equally charged and repel each other to a distance of 0.20 m. The charge on each of the sphere is a21×10-8 C. The value of a will be ___.[Given g=10 m s-2]