Question

7. Which of the following cells shown in figure is
equivalent to a parallel combination of two
identical cells 'vith emf and internal resistance of
each cell being 4 V and 4.2 respectively?
​

Answer 1

It's too simple dear

First equivalent resistance will be

1/R = 1/r1 + 1/r2

= 1/4 + 1/4

R = 2 ohm

Now

Equivalent emf will be

V/R = V1 / r1 + V2/r2

V/2 = 4/4 + 4/4

V = 4 volt

So 4th option is correct

Answered by an IIT JEE ASPIRANT and all India mathematics OLYMPIAD TOPPER in class 10th