Question

A few storage cells in series are to be charged from 30v supply if emf of the each cell is 1.35v and internal resistance 0.1 ohm the Charging current is 3A in this arrangement how many cells can be charged and what extra resistance is required to connect in series with circuit ?​

Answer 1

Answer:

Let n be the maximum number of cells in series which can be change and R is the extra resistance required if f is the currentin the circuit then (nr+R)1=30-nε

Hence ε=1.35V,r=0.1Ωandt=3.0A

Thus (n×0.1+R)×3=30-n×1.35n(1.35+0.3)+3R=m30or1.65n+3R=50...(i)

or n+ 3 /1.65  R= 30/ 1.65   =18+ 30 /165

 ∴n=3n and  3R /1.65 = 30 /165   orR=0.1Ω

Explanation: