The dot in Fig. 19-17b represents the initial state of a gas, and the isotherm through the dot...

The dot in Fig. 19-17b represents the initial state of a gas, and the isotherm through the dot divides the p-V diagram into regions 1 and 2. For the following processes, determine whether the  change AEir* in the internal energy of the gas is positive, negative, or zero: (a) the gas moves up along the isotherm, (b) it moves down along the isotherm, (c) it moves to anywhere in region L, and (d) it moves to anywhere in rcgton2.

Fig,19-17