The capacity of a parallel plate condenserr is `5mF`. When a glas plate is introduced between the plates of the condenser, its potential difference reduces to (1/8)th of the original value. The value of the dielectric constant of glass is

Options

A. 6
B. 8
C. 4
D. 10

Answer

B

Explanation

`(C_(2))/(C_(1))=(epsi_(0)KA)/(d)xx(d)/(epsi_(0)A)=K` . . (1)
and `C_(1)=(Q)/(V) and C_(2)=(Q)/(V//8)=(8Q)/(V)`
`therefore (C_(2))/(C_(1))=8` . .. (2) `therefore`from (1) and (2) K=8