(2) the piston is fixed so that it cannot move. (a) In which
case does the gas have the higher temperature after addition
of the electrical energy? (b) Identify the sign (positive, nega-
tive, or zero) of q and w in each case? (c) In which case is ΔE
for the system (the gas in the cylinder) larger?
Consider a system consisting of two oppositely charged
spheres hanging by strings and separated by a distance r₁,
as shown in the accompanying illustration. Suppose they
are separated to a larger distance r₂ by moving them apart.
(a) What change, if any, has occurred in the potential energy
of the system? (b) What effect, if any, does this process have
on the value of ΔE? (c) What can you say about q and w for
this process?