Question

Rate of dissipation of Joule’s heat in resistance per unit volume is :- (symbols have usual meaning)

• A. $\sigma E$
• B. $\sigma L$
• C. $JE$
• D. None

Answer 1

Answer: (C)

$\frac{dH}{dt}\times \frac{1}{V}=\frac{i^{2}R}{A\ell }=\frac{i}{A}\frac{iR}{\ell }=J\frac{V}{\ell }$
$=\frac{JE\ell }{\ell }=JE$