A metal bar is used to conduct heat.When the temperature at one end is 100°C and at the other is 20°C,heat is transferred at a rate of 32 J/s.The bar is then stretched uniformly to twice its original length.If again it has ends at 100°C and 20°C,at what rate will heat be transferred between it ends?
A) 4 J/s
B) 8 J/s
C) 16 J/s
D) 32 J/s

Question

Quizplus · Accepted Answer

When the bar is stretched to twice its length, its cross-sectional area is halved, reducing the rate of heat transfer by a factor of 4 (since rate is proportional to area and inversely proportional to length). Thus, the new rate is 32 J/s divided by 4, which is 8 J/s.

A Metal Bar Is Used to Conduct Heat