Question

The total length of potentiometer wire is 10 m. The distance between the null points on the potentiometer wire for two cells is 60 cm. If the difference between the emfs of the cells is 0.4 V, the potential gradient along the wire is____.

• A. $\frac{3}{2}V/m$
• B. $\frac{1}{3}V/m$
• C. $\frac{2}{3}V/m$
• D. $\frac{1}{2}V/m$

Answer 1

The correct option is C

$\frac{2}{3}V/m$

${\lambda }_1-{\lambda }_2=60cm$

$E_1-E_2=0.4$

$k{\lambda }_1-k{\lambda }_2=0.4$

$k({\lambda }_1-{\lambda }_2)=0.4$

$k=\frac{0.4}{60}=\frac{2}{3}V/m$