In a series of experiments, block B is to be placed in a thermally

insulated container with block A, which has the same mass as

block B. In each experiment, block

B is initially at a certain temperature

TB, but temperature TA of block A

is changed from experiment to experiment.

Let Tf represent the final

temperature of the two blocks

when they reach thermal equilibrium

in any of the experiments.

Figure 18-52 gives temperature Tf

versus the initial temperature TA

for a range of possible values of

TA, from TA1 _ 0 K to TA2 _ 500 K.The vertical axis scale is set by

Tfs _ 400 K.What are (a) temperature TB and (b) the ratio cB/cA of

the specific heats of the blocks?