question_answer

A 10m long wire of resistance\[20\Omega \] is connected in series with a battery of emf 3V a resistance of\[10\Omega \]. The potential gradient along the wire (in V/m) is:

A) 0.02                             

B) 0.1      

C) 0.2                               

D) 1.2

Correct Answer: C

Solution :

[c]  \[3=I\text{  }\!\![\!\!\text{ }20+10]\] \[I=\frac{1}{10}A\] \[V\text{  }\!\![\!\!\text{ }across\text{ }wire]=I{{R}_{w}}\] \[=\frac{1}{10}\times 20=2v\] Potential gradient \[\frac{V}{\ell }=\frac{2}{10}\Rightarrow 0.2V/cm\]