Question

11. Highlight your answer: In a double slit experiment with slits 1.00x10^-5m apart, light casts the first bright

band 3.00x10^-2m from the central bright spot. If the screen is 0.650 m away, what is the wavelength of
this light?

Answer 1

λ ≈ 462 nm

Step-by-step explanation:

Given:-

- The slit separation, a = 10^-5 m

- The first bright fringe occurs at, y = 0.03 m from central order

- The distance between the screen and slit, L = 0.65 m

Find:-

what is the wavelength of this light?

Solution:-

- The Young's double slit experiment gives us the relation for the interaction of a light with wavelength ( λ ) that pass through 2-slits with separation ( a ) and interfere constructively or destructively at the the screen Hence, forming an interference pattern of bright and dark fringes.

- The relation for separation ( y ) between bright fringes is related to the above mentioned parameters as given below:

y = L*n*λ / a

Where,

n: The order of fringe from central

Re-arrange for wavelength ( λ ).

- The order of first bright fringe is n = 1:

λ = y*a / L

λ = 0.03*0.00001 / 0.65

λ = 4.61538 * 10^-7 m

λ ≈ 462 nm