A parallel plate capacitor with air between the plates has a capacitance of \(8~\text{pF}\). What will be the capacitance if the distance between the plates is reduced by half, and the space between them is filled with a substance of dielectric constant \(6\)?
1. \(48~\text{pF}\)
2. \(8~\text{pF}\)
3. \(96~\text{pF}\)
4. \(60~\text{pF}\)

A parallel plate capacitor is to be designed with a voltage rating of 1 kV, using a material of dielectric constant 3 and dielectric strength of about 10⁷ V m^-1. For safety, we should like the field never to exceed, say 10% of the dielectric strength. What minimum area of the plates is required to have a capacitance of 50 pF?
 
1. 19 cm²
2. 17 cm²
3. 15 cm²
4. 23 cm²