Red light of wavelength 630 nm passes through two slits and then onto a screen that is 1.4 m from the slits. the center of the 3rd order bright band on the screen is separated from the central maximum by 0.76 cm . a)determine the frequency of the light.
b)determine the slit separation.
c)determine the angle of the third-order bright band.

Part a)

Part b)

Part c)

Explanation:

Part a)

As we know that the speed of light is given as

now the frequency of the light is given as

so we have

Part b)

Position of Nth maximum intensity on the screen is given as

so here we know for 3rd order maximum intensity

n = 3

L = 1.4 m

Part c)

angle of third order maximum is given as

i think the answer is a, hope this is right, that would be my best guess.

heat the gas and measure the pressure