1) A capacitor has a charge of 0.002C when it is connected across a 100V battery, Find its capacitance.
2) A capacitor has a capacitance of 6.40uF. How much charge must be removed to lower the potential difference of its plate by 50.0V?
3) The plates of a parallel-plate capacitor have areas of 40cm2 and are separated by 0.2mm of waxed paper (K=2.2). Find its capacitance.