A thin metallic spherical shell contains a charge +10 μC on it. A point charge +2 μC is placed at the centre of the shell and another charge +5 μC is placed outside it as shown. The force on the charge +2 μC at the centre is:
Zero
The charge +2 μC at the center of the metallic spherical shell induces an equal and opposite charge (-2 μC) on the inner surface of the shell. However, the shell itself has a net charge of +10 μC, which is distributed uniformly on the outer surface. Since the shell is conducting and spherical, it produces no electric field inside, meaning the charge +2 μC experiences no force. Thus, the net force on the charge at the center is zero.
Two charged particles, placed at a distance d apart in vacuum, exert a force F on each other. Now, each of the charges is doubled. To keep the force unchanged, the distance between the charges should be changed to:
When a slab of insulating material 4 mm thick is introduced between the plates of a parallel plate capacitor of separation 4 mm, it is found that the distance between the plates has to be increased by 3.2 mm to restore the capacity to its original value. The dielectric constant of the material is:
Match List - I with List - II.
| List - I | List - II |
|---|---|
| (A) Electric Field | (I) [LTA] |
| (B) Electric Flux | (II) [L2] |
| (C) Electric Dipole Moment | (III) [ML3T−3A−1] |
| (D) Area Vector Element | (IV) [MLT−3A−1] |
Choose the correct answer from the options given below:
A thin metallic spherical shell contains a charge +10 μC on it. A point charge +2 μC is placed at the centre of the shell and another charge +5 μC is placed outside it as shown. The force on the charge +2 μC at the centre is:

In the figure, an α-particle moves a distance l in a uniform electric field E as shown. Does the Electric Field do a positive or a negative work on the α-particle? Does the electric potential energy of the α-particle increase or decrease?
