Question

4. In an interference experiment, yellow light of wavelength 585 nm illuminates a double slit. If the screen is 1.25 m away and the distance between the central max and the ninth-order dark spot is 3.0 cm, find the slit separation.

7. Red light of wavelength 650 nm is incident on a diffraction grating with 2000 lines/cm. Find the order number of the nodal line occurring at 11.25 degrees.  

Answer 1

here L = 1.25 m

d = slit separation

lambda = 585 nm

y = 0.03 m

m = 9

so d = 0.00023156 m = 0.23156 mm

7)

distance between two lines in diffraction grating = 0.000005 m

as

so m = 2

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