To get a maximum current through a resistance of `2.5Omega` one can use m rows of cells each row having n cells . The internal resistance of each cell is `0.5Omega`. What are the values of m and n, if the total number of cells are 20?

Options

A. `m=2, n=10`
B. m=4, n=5
C. m=5, n=4
D. n=2, m=10

Answer

A

Explanation

Total number of cells `(m+n)=20`
For maximum current, R = nr/m ….(i)
`rArr " " 2.5=n xx0.5//m` or n = 5 m
From Eq. (i), `m xx 5m = 20` , or `m^(2)=4`
`rArr m = 2`, therefore `n = 5xx2=10`