Question
Assertion : The electrical conductivity of earth's atmosphere decrease with altitude.
Reason : The high energy particles (i.e. $\gamma$-rays and cosmic rays) coming from outer space and entering our earth's atmosphere causes ionisation of the atoms of the gases present there and the pressure of gases decreases with increase in altitude.
Reason : The high energy particles (i.e. $\gamma$-rays and cosmic rays) coming from outer space and entering our earth's atmosphere causes ionisation of the atoms of the gases present there and the pressure of gases decreases with increase in altitude.