(a) Calculate the charge stored on a 3-pF capacitor with 20 V across it. (b) Find the energy stored in the capacitor.

(a) The charge stored on a capacitor can be calculated using the formula Q = C * V, where Q is the charge, C is the capacitance, and V is the voltage. In this case, the capacitance is 3 pF (picofarads) and the voltage is 20 V. Therefore, the charge stored on the capacitor is Q = 3 pF * 20 V = 60 pC (picocoulombs).<br /><br />(b) The energy stored in a capacitor can be calculated using the formula E = 0.5 * C * V^2, where E is the energy, C is the capacitance, and V is the voltage. In this case, the capacitance is 3 pF and the voltage is 20 V. Therefore, the energy stored in the capacitor is E = 0.5 * 3 pF * (20 V)^2 = 60 μJ (microjoules).