Question

36 cells, each of emf 4V are connected in series and kept in a box. The combination shows an emf of 88V on the outside. Calculate the number of cells reversed.

(a) 2

(b) 5

(c) 10

(d) 7

I got this question in my homework.

I'm obligated to ask this question of Current Electricity topic in portion Current Electricity of Physics – Class 12

Answer 1

The correct option is (d) 7

To explain I would say: Number of cells (n) = 36; Emf of each cell (e) = 4V; Total emf (E) = 88V;

Let the number of reversed cells be ‘y’

The required equation: EEFF = n × e – 2y × e

88 = 36 × 4 – 2y × 4

88 = 144 – 8y

8y = 56

y = 7

Therefore, there are 7 reversed cells.