Question

A parallel plate capacitor having plates of area S and plate separation d, has capacitance C₁ in air. When
two dielectrics of different relative permittivities (????₁ = 2 and ????₂ = 4) are introduced between the two plates
as shown in the figure, the capacitance becomes C₂. The ratio C₂/C₁ is
(A) 6/5 (B) 5/3
(C) 7/5 (D) 7/3

Answer 1

Answer:

Capacitance

d

ϵ

0

A

C

3

and C

4

are in series.

C

1

=

d

ϵ

0

S

,C

3

=

2

d

ϵ

1

2

S

, C

4

=

2

d

ϵ

2

2

S

,C

5

=

d

ϵ

1

2

S

,C

34

=

C

3

+C

4

C

3

C

4

C

2

=C

34

+C

5

=

3

7

d

ϵ

0

S

C

1

C

2

=

3

7

solution