Question

A battery has e.m.f. $4V$ and internal resistance ${}^{\prime }{r}^{\prime }$. When this battery is connected to an internal resistance of $2ohms$, a current of $1amp$. flows in the circuit. How much current will flow if the terminals of the battery are connected directly :-

• A. $1A$
• B. $2A$
• C. $4A$
• D. $infinite$

Answer 1

Answer: (B)

$2A$

Current in the circuit is $I=\frac{E}{r+R}=\frac{4}{r+2}=1$
or $2+r=4$
or $r=2\Omega$
When the terminals of battery are connected directly, the current $=E/r=4/2=2A$