Question

Four identical capacitors are connected in series with a `10 V` battery as shown in the figure. The point `N` is earthed. The potentials of points `A` and `B` are
`
A. `10V,0V`
B. `7.5V,-2.5V`
C. `5V,-5V`
D. `7.5V,2.5V`

Answer 1

Correct Answer - B
All capacitors have equal capacitance. Hence equal potential drop `(=2.5V)` will take place across all capacitors.
`V_N-V_B=2.5V`
`=0-V_B=2.5V`
`:. V_B=-2.5V`
Further, `V_A-V_N=3(2.5)V`
`=7.5N`
`:. V_A=+7.5N` (as `V_N=0`)