Question

S
31. A parallel plate condenser of capacity 5uF is
kept connected to a battery of emf 10v. If the space
between the plates is filled with a medium of dielectric
constant 12, then the additional charge taken from
the battery is
1) 400 uc 2) 450 uc 3) 500 uc 4) 550 uc
(D
S

Answer 1

Given that,

Capacitor = 5 μF

Emf = 10 V

Dielectric constant k = 12

We need to calculate the charge

Using formula of charge

$Q = CV$

Where, C = capacitor

V = voltage

Q = charge

Put the value into the formula

$Q=5\times10$

$Q = 50\ \mu C$

If the space  between the plates is filled with a medium of dielectric  constant

We need to calculate the capacitor when capacitor plates are filled with dielectric

Using formula of capacitor

$C'=kC$

Put the value into the formula

$C'=5\times12$

$C'=60\ \mu F$

We need to calculate the new charge

Using formula of charge

$Q'=C'V$

Put the value into the formula

$Q'=60\times10$

$Q'=600\ \mu C$

We need to calculate the additional charge taken from  the battery

Using formula of additional charge

$Q''=Q'-Q$

Put the value into the formula

$Q''=600-50$

$Q''=550\ \mu C$

Hence, The additional charge taken from  the battery is 550 μC.

(4) is correct option