Two straight metallic wires of equal length and diameter carry the same constant current
PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity
Problem
Two straight metallic wires of equal length and diameter carry the same constant current. Wire A is made of nichrome, while wire B is made of copper. Which of the following best explains why wire A becomes noticeably hotter than wire B after a short time?
(a) Nichrome has a much lower thermal conductivity than copper, so heat that is generated inside the wire is not quickly conducted away, causing its temperature to rise higher.
(b) Nichrome has a larger resistivity than copper, so for the same current it converts electrical energy to thermal energy at a higher rate.
(c) Nichrome has a lower specific heat capacity than copper, so the same amount of energy raises its temperature more, making it feel hotter.
(d) Because P=RV2, the higher resistance of nichrome means it dissipates more power for the same current.