please make sure you have the right answer In the circuit in

please make sure you have the right answer.

In the circuit in the figure below, the emf equals 58.0 V and the capacitance equals 2.15 µF. Switch S is opened after having been closed for a long time, and 5.10 s later the voltage drop across the resistor is 28.5 V. Find the resistance of the resistor.
..... M

Solution

equation for volatge in RC ckt while charging is

V= V0(e^-t/RC)

where t is time

R is resistance

C is capacitance

so

e^-t/RC = V/Vo = 28.5/58

e^-t/RC = 0,4913

-t/RC = ln(0.4913)

-t = -0.7105 * RC

t = 0.7105 * R * 2.15 e-6

R = 5.1/(0.7105* 2.15 e -6)

R = 3.34 MOHMS