For what distance is ray optics a good approximation when the aperture is 3 mm wide and the wavelength is 500 nm?

Estimate the distance for which ray optics is good approximation for an aperture of 4 mm and wavelength 400 nm.

a) At 35°C and 700 mm of Hg pressure , a gas occupies a 500 mL volume . What wil be its pressure when the temperature is 15° C and the volume of the gas is 450 ml?

At 35^@C and 700 mm of Hg pressure, a gas occupies a 500mL volume. What will be its pressure when the temperature is 15^@C and the volume of the gas is 450ml?