Two identical condensers M and N are connected in series with a battery. The space between the plates of M is completely filled with a dielectric medium of dielectric constant 8 and a copper plate of thickness `d/2`is introduced between the plates of N. (d is the distance between the plates). Then potential differences across M and N are, respectively, in the ratio

Options

A. `1:4`
B. `4:1`
C. `3:8`
D. `1:6`

Answer

(a)

Explanation

capacitance of condencer , `C_(N) = C'/2`
`C' = 4Aepsilon_(0)/d = 4C`
`rArr C_(N) = 4C/2 = 2C`
When two condensers are connected in series ,
`V_(M):V_(N) = 1/C_(M):1/C_(N) = 1/8C , 1/2C = 1 : 4`