An air-filled capacitor consists of two parallel plates, each with an area of 7.60 $\mathrm{cm}^{2}$ and separated by a distance of 1.80 $\mathrm{mm}$ . If a $20.0-\mathrm{V}$ potential difference is applied to these plates, calculate (a) the electric field between the plates, (b) the capacitance, and (c) the charge on each plate.