Question

A $1^{\circ }C$ rise in temperature is observed in a conductor by passing a certain current. If the current is doubled, then the rise in temperature is approximately

• A. ${2.5}^{\circ }C$
• B. $4^{\circ }C$
• C. $2^{\circ }C$
• D. $1^{\circ }C$

Answer 1

Answer: (B)

$4^{\circ }C$

We know that heat $H=i^{2}Rt$ so $H\propto i^2$
So when en current i is double, heat will four times increase.
As heat is proportional to change in temperature i.e, $H\propto \Delta T$ so the rise in temperature will be $4^{o}C$.