Let us suppose, capacitors of capacitance C1 and C2 are connected in series and voltage ‘V’ is applied across it.
The voltage across capacitor C1 is ‘V1’ and the voltage across the capacitors C2 is ‘V2’.
V = V1 + V2.
Q = CV
V = Q/C
Q/Ceq = Q/C1 + Q/C2.
Or
1/Ceq = 1/C1 + 1/C2.
Similarly, for the ‘n’ number of capacitors which is connected in the series, the net capacitance is given as,
1/Ceq = 1/C1 + 1/C2 + 1/C3 + …………. + 1/Cn.
Referebce Source:
[1] Sharma, B.M. Physics for Joint Entrance Examination , JEE (Advanced). CENGAGE LEARNING, EDITION: 2014, 2012.
[2] Pandey, DC. Understanding Physics for JEE Main and Advanced. Meerut, Arihant.