Question

In figure, at steady state what is the potential difference between the points $A$,$B$ and between $B$,$C$ respectively ?

• A. $100V$ both
• B. $V_{AB}=75V,V_{BC}=25V$
• C. $V_{AB}=25V,V_{BC}=75V$
• D. $V_{AB}=50V,V_{BC}=50V$

Answer 1

The correct option is C $V_{AB}=25V,V_{BC}=75V$

At steady steady, current through capacitors is zero. Hence effect of resistors in the circuit can be neglected.



When capacitors are connected in series with a battery of potential $V$.
Potential difference across each capacitor is given by
$V_1=\left[\frac{C_2}{C_1+C_2}\right]V$ and
$V_2=\left[\frac{C_1}{C_1+C_2}\right]V$

Now,
$V_1=V_{AB}=\left[\frac{2}{2+6}\right]100=25V$
$V_2=V_{BC}=\left[\frac{6}{2+6}\right]100=75V$