Question

A sphere $S_{1}$ of radius $R$, encloses a total charge $q$. If there is another concentric sphere $S _{2}$ of radius $2 R$ and there be no additional charges between $S_1$ and $S _{2} .$ What is the ratio of electric flux through $S _{1}$ and $S _{2} ?$

• A. 1.5
• B. 2
• C. 1
• D. 0.5

Answer 1

Answer: (C)

$\phi=\frac{q}{\varepsilon_{0}}$
So,
$\frac{\phi_{1}}{\phi_{2}}=\frac{q_{1}}{\varepsilon_{0}} \times \frac{\varepsilon_{0}}{q_{2}}$
$=\frac{q_{1}}{q_{2}}$
$\frac{\phi_{1}}{\phi_{2}}=\frac{q}{q}=1$