Question

A $10\mu F/400V$ and a $4\mu F/100V$ capacitors are connected in series. find the maximum potential which can be applied.

• A. 100 V
• B. 500 V
• C. 400 V
• D. 140 V
• E. None of these

Answer 1

The correct option is D 140 V

As the capacitors are in series so the charge on both remains same. Charge on small capacitance $4\mu F$ is $Q=4\times {10}^{-6}\times 100=400\mu C$. Thus we can not apply charge greater than $400\mu C$. The potential of capacitance $10\mu F$ for this charge is $V=400/10=40V$.
Thus the maximum potential applied is $(100+40)=140V$