The distance between the 1st and 2nd maxima is 0.3 cm when the screen is located 2 m away. If d = 0.4 mm, a) what is the wavelength?

b) what is the size of central peak?

a) The wavelength of light is 6*10^-7 m.

b) The size of the central peak is 6*10^-3 m.

Explanation:

let:

α be the distance between the 1st and 2nd maxima

d = 0.4 mm be the grating slit space

X be the distance to the screen

a) α = λ*X/d

λ = α*d/X

= (0.3*10^-2) * (0.4*10^-3) / (2)

= 6*10^-7 m

Therefore, the wavelength of light is 6*10^-7 m.

b) the size of the central peak is given by:

D = 2*λ*X/d

= 2 * (6*10^-7) * (2) / (0.4*10^-3)

= 6*10^-3 m

Therefore, the size of the central peak is 6*10^-3 m.