Q.

A parallel plate capacitor was made with two rectangular plates, each with a length of l = 3 cm and breath of b = 1 cm. The distance between the plates is 3 μm. Out of the following, which are the ways to increase the capacitance by a factor of 10

A. l = 30 cm, b = 1 cm, d = 1 μm

B. l = 3 cm, b = 1 cm, d = 30 μm

C. l = 6 cm, b = 5 cm, d = 3 μm

D. l = 1 cm, b = 1 cm, d = 10 μm

E. l = 5 cm, b = 2 cm, d = 1 μm

Choose the correct answer from the options given below:          [2025]

1 C and E only  
2 B and D only  
3 A only  
4 C only  

Ans.

(1)

We know C=Aε0d=blε0d

So, to increase the capacitance by factor 10(Ad) has to increase by factor 10.

For option (A)     C'=30C

For option (B)     C'=C10

For option (C)     C'=10C

For option (D)     C'=C10

For option (E)     C'=10C