Question

A point charge causes an electric flux of $-1.0 \times 10^{3} N m ^{2} / C$ to pass through a spherical Gaussian surface of $10.0 \,cm$ radius centred on the charge. If the radius of the Gaussian surface was doubled, how much flux would pass through the surface?

• A. $-1.0 \times 10^{3} N m ^{2} / C$
• B. $-2.0 \times 10^{3} N m ^{2} / C$
• C. $-3.0 \times 10^{3} N m ^{2} / C$
• D. $-4.0 \times 10^{3} N m ^{2} / C$

Answer 1

Answer: (A)

Here, $\phi_{E}=-1.0 \times 10^{3} N m ^{2} / C , r=10.0\, cm$
If the radius of Gaussian surface was doubled, flux passing through the surface would remain the same. This is because flux depends only on charge present inside the surface.