Question

7. A light source has two spectral components, one with unknown wavelength and the other with wavelength 620 nm. When light from the source is incident to a thin rectangular slit, a screen behind the slit shows the second diffraction minimum from the 620 nm component at the exact same location as the third diffraction minimum from the unknown wavelength component. What is the unknown wavelength?

Answer 1

Step-by-step explanation:

Problem relates to diffraction of light . Location for 2 nd diffraction minima is

`x=2*(\lambda D)/(d)` where λ is wavelength of light , D is distance of screen , d is slit width .

Puting the values

`x=2*(620D)/(d)`

for unknown wavelength , position of third diffraction is

`x=3*(\lambda D)/(d)`

from these two equations

`x=2*(620D)/(d)`
`=3*(\lambda D)/(d)`

λ = 413.33 nm .