181.

Two charged spheres separated by a distance 'd' exert some force on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force exerted, if all other conditions are same?

• F/2

• F

• 2F

• 4F

A hexagon of side 8 cm has a charge 4 µC at each of its vertices. The potential at the centre of the hexagon is

• 2.7 × 10⁶ V

• 7.2 × 10¹¹ V

• 2.5 × 10¹² V

• 3.4 × 10⁴ V

A 5 µF capacitor is charged by being connected to a 3 V battery. The battery is then disconnected. If the resistance of the dielectric material between the capacitor plates is 10⁹ Ω, what is the charge remaining on the capacitor 1 h after it has been disconnected ?

• 1.5 × 10^-5 C

• 7.4 × 10^-6 C

• 5.4 × 10^-6 C

• 8.4 × 10^-5 C

A metallic solid sphere is placed in a uniform electric field. Which path, the lines of force follow as shown in figure?

• 1

• 2

• 3

• 4

2, 4 and 6 S are the conductances of three conductors. When they are joined in parallel, their equivalent conductance will be

• 12 S

• ( 1/12 ) S

• ( 12 /11 ) S

• 11/12 S

The diameter of the plate of a parallel plate condenser is 6 cm. If its capacity is equal to that of a sphere of diameter 200 cm, the separation between the plates of the condenser is

• 4·5 × 10^-4 m

• 2·25 × 10^-4 m

• 6·75 × 10^-4 m

• 9 × 10^-4 m

In a uniform electric field a charge of 3 C experiences a force of 3000 N. The potential difference between two points 1 cm apart along the electric line of force will be

• 10 V

• 30 V

• 300 V

• 100 V

Assertion: On going away from a point charge or a small electric dipole, electric field decreases at the same rate in both the cases. 

Reason: Electric field is inversely proportional to square of distance from the charge or on electric dipole.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• if both assertion and reason are false.

Assertion: If a conductor is given charge then no excess inner charge appears. 

Reason: Electric field inside conductor is zero.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Gaussian surface is considered carefully. 

Reason:  The point where electric field to be calculated should be with in the surface

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.