2018 · Q39
A wire of copper having length l and area of cross-section A is taken and a current I is flown through it. The power dissipated in the wire is P. If we take an aluminium wire having same dimensions and pass the same current through it, the power dissipated will be
General KnowledgePhysics
- AP
- B< P
- C> P
- D2P
Explanation
Power dissipated is P = I²R. Aluminium's resistivity is higher than copper's, so an aluminium wire of the same dimensions has greater resistance. With the same current flowing, it therefore dissipates more power. Hence the power dissipated is greater than P.