Question

If $E$ denotes electric field in a uniform conductor, $I$ corresponding current through it, $v_{d}$ drift velocity of electrons and $P$ denotes thermal power produced in the conductor, then which of the following graphs is/are correct ?

• A. 1, 2 and 3 are correct
• B. 1 and 2 are correct
• C. 2 and 4 are correct
• D. 1 and 3 are correct

Answer 1

Answer: (A)

$E=\frac{I R}{L}=\frac{I \rho l}{A}=n e v_{d} \rho l$
ie, $v_{d} \propto E$ (Straight line)
$P=I^{2} R=\left(\frac{E A}{l}\right)^{2} R$
ie, $P \propto E^{2}$ (Symmetric parabola)
Also $P \propto I^{2}$ (Symmetric parabola)