Question

a series parallel combination battery consisting of large numberN=300 of identical cells

Answer 1

for series combination current is always equal whereas in parallel combination potential difference is always equal or we can say constant.

as we know that the group of cells are battery

Answer 2

Lets assume, there are 'n' cells in each row and a total of 'm' rows are connected in parallel combination.

Thus,

m x n = 300

Now as the question is incomplete, I'm assuming an external resistance 'R' is attached in the circuit and the internal resistance of the cells are 'r'.

Now, each row provides an emf = nE

the equivalent resistance of each row is 'nr'

Then, for 'm' number of rows attached in parallel combination, the equivalent resistance is 'nr/m'

emf across the external resistance 'R' is 'nE'

Thus, current flowing = [total emf/total resistance]

or, I = (nE) / (R + nr/m)

or, I = mnE / (mR + nr)

Now put the values this equation and u'll get the missing value.