Moderate# RC Circuit and First Order Linear ODE

DIFFEQ-YKN6SS

Consider a circuit with only one capacitor and one resistor inside. The capacity of the capacitor is $C=2\ F$ while the resistance of the resistor is $R=1.5\ \Omega$.

Initially, the voltage on the capacitor is $U=0.1\ V$.

At what time (unit: second) is the voltage on the capacitor $0.05\ V$?