4.

(A) State what is meant by monochromatic rays?

(B) Monochromatic light falling on two slits 10/100 mm apart produces the fifth-order fringe at a 27/5 angle. What is the wavelength of light in nanometers?

(C) Suppose a light with a wavelength of 10x106m passes a pair of slits with a separation of 37x10-4 m. Determine the angle which corresponds to the first bright fringe

(D) Blue light (wavelength 400nm) is sent through a double slit. The slits are 10/10 nm apart. The light then hits a screen that is 37 cm behind the double slit. How far is the first bright fringe from the second bright fringe?