What size capacitor is required if it is to have 24 μC of charge on its plates when a 6 V supply is connected across it? What is the potential difference between the plates of a 4 μF capacitor when...

What size capacitor is required if it is to have 24 μC of charge on its plates when a 6 V supply is connected across it?

What is the potential difference between the plates of a 4 μF capacitor when there is a charge of 16 μC on its plates?