In Fig$\mathrm{.}30\mathrm{.}11$ in the textbook, suppose that EE $=69\mathrm{.}0$ VV $,$ RR $=210$ and LL $=0\mathrm{.}160$ HH $.$ With switch S$2$S$2$ open, switch S$1$S$1$ is left closed until a constant current is established. Then S$2$S$2$ is closed and S$1$S$1$ opened, taking the battery out of the circuit. c$.$ What is the potential difference between points b and c at tt $=4\mathrm{.}30104$ ss $?$