Question

Earth's atmosphere is constantly bombarded by cosmic ray protons that originate somewhere in space. If the protons all passed through the atmosphere, each square meter of Earth's surface would intercept protons at the average rate of 1800 protons per second. What would be the electric current in amperes intercepted by a 14 x 10⁷ km² area on the planet?

Answer 1

1 km^2 = 10^6 m^2

Current = charge/unit time = charge of proton * number of protons/second

Current = charge of proton * protons/m^2/s^* area

= 1.6x10^-19 C * 1800 protons/m^/s * 14x10^7x10^6 m^2 = 0.04032A