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

• A

  ${\phi }_1=4{\phi }_2$

• B

  ${\phi }_1=2{\phi }_2$

• C

  ${\phi }_1={\phi }_2$

• D

  ${\phi }_1=\frac{{\phi }_2}{2}$