The figure shows a spherical capacitor. The inner sphere has radius $a=1.00 \mathrm{~cm},$ and the outer sphere has radius $b=1.10 \mathrm{~cm} .$ The battery supplies $V_{\mathrm{emf}}=10.0 \mathrm{~V},$ and the resistor has a value of $R=10.0 \mathrm{M} \Omega$
a) Determine the time constant of the RC circuit.
b) Determine how much charge has accumulated on the capacitor after switch S has been closed for $0.1 \mathrm{~ms}$