Two identical capacitor `C_(1)` and `C_(2)` are connected in series with a battery. They are fully charged. Now a dielectric slab is inserted between the plates of `C_(2)`. The potential across `C_(1)` will :

Options

A. increase
B. decrease
C. remain same
D. depend on internal resistance of the cell

Answer

A

Explanation

Potential difference across 'C'
`V_(1)=(C_(2)V)/(C_(1)+C_(2))=(V)/(1+C_(1)//C_(2))`
When dielectric is inserted `C_(2)` will increase.