Conduction

The two ends of a rod of length and a uniform cross-sectional area are kept at two temperatures The rate of heat transfer through the rod in a steady state is given by:

1.

2.

3.

4.

A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod when placed in thermal contact with the two reservoirs at the same time?

1. Q /4

2. Q/16

3. 2Q

4. Q/2

Two rods and of different materials are welded together as shown in the figure. Their thermal conductivities are and The thermal conductivity of the composite rod will be:

1.		2.
3.		4.

Three identical heat conducting rods are connected in series as shown in the figure. The rods on the sides have thermal conductivity while that in the middle has thermal conductivity . The left end of the combination is maintained at temperature and the right end at The rods are thermally insulated from outside. In the steady state, temperature at the left junction is and that at the right junction is . The ratio is:

1.		2.
3.		4.