Question

A potentiometer wire is 10 m long and has a resistance of $20\Omega$. It is connected in series with a battery of emf 3V and a resistance of $10\Omega$. The potential gradient along the wire in $V{m}^{-1}$ is

• A. 0.01
• B. 0.02
• C. 0.1
• D. 0.2

Answer 1

The correct option is D 0.2



$r=10\Omega ,R=20\Omega \epsilon =3V$
$i=\frac{\epsilon }{R+r}=\frac{3}{30}=0.1A$
$V_R=iR=0.1\times 20=2V$
Potential gradient along the wire is $\frac{V}{L}=\frac{2}{10}=0.2V{m}^{-1}$