Question

The potential difference between the terminals of a battery of emf 6.0 V and internal resistance 1 $\Omega$ drops to 5.8 V when connected across an external resistor. Find the resistance of the external resistor.

Answer 1

$E{=}^{\prime }6v,R=1\Omega ,$

$v=5.8V,R=?$

$i=\frac{E}{R+r}=\frac{6}{R+1}$

$V=E-iR$

$\Rightarrow 5.8=6-\frac{6}{R+1}\times 1$

$\Rightarrow \frac{6}{R+1}=0.2$

$R+1=\frac{6}{0.2}=30$

$R=29\Omega$