Question

5. Protons in cosmic rays strike the Earth's upper atmosphere at an average rate of 1200 protons per square meter per second. What total current (in Coulombs per second, or Amperes) does the Earth receive from these cosmic rays? (For the radius of the Earth, use Re- 6.38 x 10s meters.)

Answer 1

$\\area\;of\;the\;earth's\;surface\;A=4\pi R^2\\\\ number\;of\;protons\;hitting\;surface\;per\;second\;n=1200\times A\\\\ total\;current\;received\;i=n\;e\\\\ e=charge\;of\;proton=1.609\times 10^{-19}\;C\\\\ i=1200\times 4\times \pi\times (6.38\times 10^6)^2\times 1.609\times 10^{-19}\;A\\\\ i=0.098\;A$