Answer:
b. 450 nm
Step-by-step explanation:
The wavelength of light can be calculated by using the formula derived in Young's double slit experiment. The formula is as follows:
Δx = λL/d
Δx/2 = λL/2d
where,
Δx/2 = half distance between consecutive dark fringes = width of central maximum = 0.75 cm = 0.0075 m
λ = wavelength of light = ?
L = Distance of Screen = 1.25 m
d = width of slit = 0.15 mm = 0.00015 m
Therefore,
0.0075 m = λ(1.25 m)/(0.00015 m)
λ = (0.0075 m)(0.00015 m)/2(1.25 m)
λ = 4.5 x 10⁻⁷ m = 450 nm
Thus, the correct option is:
b. 450 nm