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CUET
Physics
Wave Optics
A slit of width a is illuminated by white light. The first minimum for light of wavelength 3900 Å will fall at θ = 60°, if a is
3900 Å
1950 Å
7880 Å
4503 Å
For first minimum,
$a\sin θ = λ$
$⇒a=\frac{λ}{\sin θ}=\frac{3900}{\sin 60}Å=4503 Å$