Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
0 votes

Potentiometer wire is of cross sectional area $8 \times 10^{-6}m^2$ and has resistivity $40 \times 10^{-8}$. If $0.2$ amp current flows through it its potential gradient is

$(a)\;10^{-2} v/m \\(b)\;2 \times 10^{-2}\;v/m \\(c)\;10^{-3} \;v/m \\(d)\;3 \times 10^{-3}\;v/m $

Can you answer this question?

1 Answer

0 votes
Potential gradient is $ \large\frac{V}{L}$ where V is potential across wire of length L.
$R= \large\frac{\rho L}{A}$
$\qquad= \large\frac{40 \times 10^{-8} \times L}{8 \times 10^{-6}}$
$\qquad= 5 \times 10^{-2}\;L$
$V= I \times R$
$\qquad= 5 \times 10^{-2} \times L \times 0.2$
$\qquad = 1 \times 10^{-2} \times L$
Potential gradient $=\large\frac{V}{L}$
$\qquad= 10^{-2}\;V/m$
Hence a is the correct answer.
answered Mar 18, 2014 by meena.p

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App