Final answer:
To find the capacitance of a parallel-plate capacitor with circular plates, use the formula C = ε_r ε_0 A / d with the given radius to calculate the plate area and the separation between plates.
Step-by-step explanation:
The question is asking to calculate the capacitance of a parallel-plate capacitor with circular plates. The capacitance of a parallel-plate capacitor is given by the equation C = ε_r ε_0 A / d, where C is the capacitance, ε_r is the relative permittivity of the dielectric material (which is 1 for a vacuum or air), ε_0 is the permittivity of free space (ε_0 = 8.854 x 10^-12 F/m), A is the area of one of the plates, and d is the separation between the plates. To calculate the area of a circle, we use the formula A = πr^2, where r is the radius. In this case, the radius is 8.4 cm or 0.084 m, so the area A will be π(0.084 m)^2.
The separation d is given as 1.5 mm, which is 0.0015 m. Plugging these values into the capacitance formula, we would calculate the capacitance of the capacitor.