Ok, here I am providing you the Electrostatics Problems of IIT Joint Entrance exam JEE

IIT JEE exam Electrostatics Problems

Q: Consider two concentric metallic shells of radii a and b, where b > a. The outer shell has charge Q but inner shell has no charge. Now, the inner shell is grounded. Find the charge on the inner shell.

Q: A capacitor has rectangular plates of length a and width b. The top plate is slightly inclined upwards such that the separation is y0 at the left and is 2y0 at the right. (where y0 << a, b). Calculate the capacitance of the system.

Q: Consider a huge charge reservoir at potential V . A spherical capacitor C1 is brought in contact with the charge reservoir and then removed. Next another spherical capacitor C2 is brought in contact with C1 and removed. We repeat this process a large number of times. Assume that potential of reservoir does not change during this exercise. Then the charge on C2 after a very long time is...

Q: Consider a circle of radius R. A point charge lies at a distance a from its center and on its axis such that R = a √3. If electric flux passing through the circle is φ then the magnitude of the point charge is ..

Q: Two identical rings, each of radius a are places co-axially at a distance a apart. Let charges Q1 and Q2 be placed uniformly on the two rings. The work done in moving a charge q from the center of one ring to that of other ring is..

Q: Find the capacitance of a system of two identical metal balls of radius a if the distance between their centers is equal to b, with b > 2a. The system is located in a uniform dielectric with permittivity
unity.

Q: An electron with initial kinetic energy K0 is ejected at point A as shown in the figure.
(a) At what minimum distance L0 should the electron be ejected so as to miss the plate?
(b) Describe the ejected electron’s trajectory if L > L0 .

1. A copper sphere contains about 5 x 10^21 atoms. Atomic weight of copper is 64 and atomic number 29. It is given positive charge of 2 x 10^(-6) C. Determine the change in its mass

Remains unchanged
Mass decreases by 1.125 x 10^(-17) kg
Mass decreases by 2.25 x 10^(-17) kg
Mass increases by 2.25 x 10^(-17) kg

2. Two charged spheres of radius ‘R’ are kept at a distance ‘d’ (d > 2R). One has a charge +q and the other -q. The force between them will be-

q*q / (4πεd*d)
> q*q / (4πεd*d)
< q*q / (4πεd*d)
None of these

3. If a point charge Q is located at the centre of a cube then find flux through one surface.

Q/ε
Q/2ε
Q/6ε
0

4. A cylinder of length L and radius b has its axis coincident with the x axis. The electric field in this region E = 45i . Find the flux through the cylinder curved surface ?

45 πb*b
-45 πb*b
0
None of these

5. In the question 4, find the flux through the right end of the cylinder ?

45πb*b
-45πb*b
0
None of these

6. A solid spherical conductor carries a charge Q. It is surrounded by a concentric uncharged spherical shell. The potential difference between the surface of solid sphere and the shell is V. If a charge of –3Q is given to the shell. Then the new potential difference between the above two points will be ?

2V
3V/4
V/2
None of the above

7. Electric potential for a point (x, y, z) is given by V = 4x volt. Electric field at point (1, 0, 2) is -

-8 V/m
8 V/m
-4 V/m
4 V/m

8. What is the dimension of dipole moment ?

M^0 L^1 T^1 A^1
M^1 L^1 T^1 A^1
M^1 L^1 T^1 A^2
M^1 L^2 T^1 A^1

9. A thin insulating rod of length L carries a uniformly distributed charge Q. Find the electric field strength at a point along its axis at a distance 'a' from the one end.

Q/(4 π ε a ( a+ l ))
Q/(2 π ε a ( a+ l ))
Q/(4 π ε a*a)
None of these

10. Dipole is made up of ?

2 charges of same magnitude and sign.
2 charges of different magnitude but same sign.
2 charges of same magnitude but different sign.
2 charges of different magnitude and different sign.