Question1
The ozone concentration in an atmosphere is measured in Dobson Units. We say that the amount of ozone is 1 DU when there are 2x10^6 molecules of Ozone in an atmospheric column with a cross-section of 1 cm^2. The average ozone absorption in atmosphere is around 300 DU.
a) compute average number of ozone molecules in an atmospheric column with a cross-section of 1 m^2?
b) What is an average number of ozone molecules in a similar column over Antarctica when the "ozone hole" is at its peak of 100 DU?
Question2
Take two long identical plane mirror strips. Illustrate lines making angles of 30o, 45o, 60o,75o and 90o on a unruled plane paper sheet fixed on a horizontal board. Place reflecting surfaces of the mirror strips along the arms of 30o angle vertically, using plasticine. Place a piece of coloured glass between two mirrors and see how numerous images of it are formed in all. Show again the experiment for other angles counting the number of images formed in each case. Tabulate number of images (n) against angle of inclination between the mirrors (q). Illustrate a graph between q and n. Do you see any relationship between these two quantities?