Question

1. The number density of ozone at z = 20km altitude is n_O3 = 5.2 x 10¹² molecules cm^-3. What thickness of this air absorbs 99% of incoming 280nm radiation? The ozone absorption cross section peaks at 280 nm with a value of σ_O3 = 2.00 x 10^-18 cm² molecule^-1. Assume ozone is the only species that absorbs this radiation, and answer in km with two significant digits.

Answer 1

Given that number density of ozone at an altitude 2 =20km is - noz = 5:2x10' mulealles [cm] thickness of or absorbs 99.4. radiation - 2800m ozone with absorptim cross section peoks aroom value of 5o = 2x10 cm² must Thickney = absorbance (hember density) xoabsorbtim in cross section) 0.99 75.2x10 12.x 2x1077) om am = 95192cm Thickney = d.g5km