You have two plates of copper, a sheet of mica (thickness 0.10 mm, k 5.4), a sheet of glass (thickness 2.0 mm, k 7.0), and a slab of paraffin (thickness 1.0 cm, k 2.0). To make a parallel-plate capacitor with the largest C, which sheet should you place between the copper plates?
Hi. Just multiply. Mica is a good bet.
Well, C is linearly proportional to k, and inversely proportional to d. So, you want to maximize the ratio k / d. Converting everything to cm, you see that mica is 0.01cm, glass is 0.2cm, and paraffin is 1.0cm. You can easily se that mica will produce the largest capacitance.
