Answer:
646.60 nm
Explanation:
Given:
wavelength of the light produced, λ₁ = 632.8 nm
Spacing between the bright fringes, y₁ = 5.50 mm
Spacing between the bright fringes when the laser is replaced,y₂ = 5.62 nm
Now,
the spacing between the bright fringes (y) is given as:
y =

where,
D is the distance between the slit and the screen
d is the distance between the slits
or

therefore, using the above relation, we have

where,
λ₂ is the wavelength of the light produced by the smaller pointer
thus, on substituting the values,we get

or
λ₂ = 646.60 nm
Hence,
the wavelength of light produced by the smaller pointer = 646.60 nm