Question

Figure shows mixed grouping of identical cells each of e.m.f. 4 V and internal resistance $1\Omega .$ This combination can be replaced by an equivalent cell between A and B having e.m.f. E and internal resistance r, where

• A. $E=72V$ $r=18\Omega$
• B. $E=24V$ $r=18\Omega$
• C. $E=72V$ $r=2\Omega$
• D. $E=24V$ $r=2\Omega$

Answer 1

The correct option is A $E=72V$ $r=18\Omega$

Total no of cells=$18$

$\therefore$ equivalent emf :-$ϵ=18\times 4v$

$=72v$

Equivalent resistance,$r=18\times 1\Omega$

$=18\Omega$