Need help please guys

What happens in a global convection cell

A20 cm long spring is attached to a wall. the spring stretches to a length of 22 cm when you pull on it with a force of 100 n. what is the spring constant

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?