two concentric conducting spheres have radii of r1 and r2, with r1 greater than r2. the capacitance is…

two concentric conducting spheres have radii of r1 and r2, with r1 greater than r2. the capacitance is proportional to (r1 - r2)/r1r2, r1r2/(r1 - r2), none of the choices are correct, r2 - r1, r2 + r1
Answer
Explanation:
Step1: Recall capacitance formula for concentric spheres
The capacitance $C$ of two - concentric conducting spheres with radii $R_1$ and $R_2$ ($R_1>R_2$) is given by $C = 4\pi\epsilon_0\frac{R_1R_2}{R_1 - R_2}$. So the capacitance is proportional to $\frac{R_1R_2}{R_1 - R_2}$.
Answer:
$R_1R_2/(R_1 - R_2)$