The capacitor in an \(R C\) circuit with a time constant of \(15 \mathrm{~ms}\) \(\mathbb{N T}\) is charged to \(10 \mathrm{~V}\). The capacitor begins to discharge at \(t=0 \mathrm{~s}\).

a. At what time will the charge on the capacitor be reduced to half its initial value?

b. At what time will the energy stored in the capacitor be reduced to half its initial value?