Question

Consider two concentric spherical surfaces $S_1$ with radius $a$ and $S_2$ with radius $2a$, both centred on the origin. There is a charge $+q$ at the origin, and no other charges. Compare the flux ${\varphi }_1$ through $S_1$ with the flux ${\varphi }_2$ through $S_2$.

• A. ${\varphi }_1=4{\varphi }_2$
• B. ${\varphi }_1=2{\varphi }_2$
• C. ${\varphi }_1={\varphi }_2$
• D. ${\varphi }_1={\varphi }_2/2$

Answer 1

The correct option is C ${\varphi }_1={\varphi }_2$

Flux through both will be the same as net charge enclosed by both is same.