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Homework Statement
Question:
Blue light of wavelength 485.6nm from a star is incident normally on a diffraction grating. The light is diffracted into a number of beams, as shown in Fig 5.4.(attached)
The angular separation of the two secondorder beams is 45.72 degrees.
Calculate the number of lines per millimetre on the grating.
Homework Equations
The Attempt at a Solution
I genuinely do not know where to start the question. I know the formula for Young's double slit experiment however this does not seem to relate to it at all. Any suggestions for starting the question would be really appreciated.
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