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IMPORTANT
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(a) Figure a shows a nonconducting rod of length L=6.00 cm and uniform linear charge density λ=+7.07 pC m-1. Assume that the electric potential is defined to be V=0 at infinity. What is V at point P at a distance d=8.00 cm along the rod's perpendicular bisector?

(b) Figure b shows an identical rod except that one half is now negatively charged. Both halves have a linear charge density of magnitude 3.68 pC m-1. With V=0 at infinity, what is V at P? Is the potential at P positive, negative or zero if P is moved in the plane of the figure by a distance of L4 (c) upward and (d) leftward?

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Important Questions on Electric Potential

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JEE Main
IMPORTANT

The thin plastic rod of length L=12.0 cm as shown in figure, has a non-uniform linear charge density λ=cx C m-1, where, c=49.9 pC m-2 (a) With V=0 at infinity, find the electric potential at point P2 on the y-axis at y=D=3.56 cm. (b) Find the electric field component Ey at P2 (c) Why cannot the field component Ex at P2 be found using the result of (a)?

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HARD
JEE Main
IMPORTANT

In the figure, particles with the charges q1=+15e and q2=-5e are fixed with a separation of d=24.0 cm. With electric potential defined to be V=0 at infinity, what are the finite (a) positive and (b) negative values of x at which the net electric potential on the x-axis is zero?

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HARD
JEE Main
IMPORTANT

Two particles of charges q1 and q2 are separated by a distance d in the figure. The net electric field due to the particles is zero at x=d/4.

(a) WithV=0 at infinity, locate (in terms of d) any point on the x-axis (other than at infinity) at which the electric potential due to the two particles is zero.

(b) If, instead the net electric potential is 0 at x=d/4, find (in terms of d) the coordinates of any point (other than at infinity) at which the net electric field is zero.

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HARD
JEE Main
IMPORTANT

Plastic rod has been bent into a circle of radius R=8.20 cm It has a charge Q1=+7.07 pC uniformly distributed along one quarter of its circumference and a charge Q2=-6 Q1 is uniformly distributed along the rest of the circumference (as shown in fig.)  With V=0 at infinity, what is the electric potential at (a) the center C of the circle and (b) point P on the central axis of the circle at distance D=2.05 cm from the center?

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MEDIUM
JEE Main
IMPORTANT
A thin, spherical, conducting shell of radius R is mounted on an isolated support and charged to a potential of -170 V. An electron is then fired directly towards the centre of the shell, from point P at a distance r from the centre of the shell (rR). What initial speed v0 is needed for the electron to just reach the shell before reversing direction?
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JEE Main
IMPORTANT

An electron is placed in an xy plane where the electric potential depends on x and y as shown, for the coordinate axes, in the figure (the potential does not depend on z). The scale of the vertical axis is set by Vs=1000 V. In unit-vector notation, what is the electric force on the electron?

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MEDIUM
JEE Main
IMPORTANT

The electric potential V in the space between two flat parallel plates 1 and 2 is V=1500 x2 (in volts), where, x (in meters) is the perpendicular distance from plate 1. At x=1.8 cm,

(a) What is the magnitude of the electric field?

(b) Is the field directed towards or away from plate 1?

HARD
JEE Main
IMPORTANT
A particle of charge q is fixed at point P, and the second particle of mass m and the same charge q is initially held a distance r1 from P. The second particle is then released. Determine its momentum when it is at a distance r2 from P. Let q=3.1 μCm=20 mg, r1=0.90 mm and r2=1.5 mm.