Page 1 - Work sheet-3

Class XII

PHYSICS

Chapter-2-Electric potential & capacitance

WORKSHEET-3

1. A slab of dielectric constant K has the same area as the plates of a parallel plate capacitor d
but has a thickness of (3d)/4, where d is the plate separation. After inserting the slab
between the plates, the capacitance

a. becomes zero.
b. becomes infinite.
c. decreases.
d. increases.

2. The energy stored in four capacitors, each of capacitance ‘C’, placed in parallel b
configuration and connected to a ‘V’ volt source is

a. CV.
2
b. 2CV .
2
c. (1/8)CV .
2
d. CV /2.
3. A capacitor is charged to store an energy U. The charging battery is then disconnected. An d
identical capacitor is now connected to the first capacitor in parallel. The energy in each
of the capacitor is

a. 3U/2.
b. U.
c. U/2.
d. U/4.

4. A potential difference of 250 volt is applied across the plates of a capacitor of 10 pF. b
What is the charge on the plates of the capacitor?

-9
a. 1.5x10 C
-9
b. 2.5x10 C
-4
c. 4.2x10 C
5
d. 1.25x10 C

5. Increasing the charge on the plates of a capacitor means b

a. increasing the capacitance.
b. increasing the potential difference between the plates.
c. decreasing the potential difference between the plates.
d. no change in the field between the plates.

6. Consider a parallel plate capacitor of capacity 10 mF with air filled in the gap between the
plates. Now one half of the space between the plates is filled with a dielectric of dielectric
constant K = 4 as shown in figure.