CUET Preparation Today
A slit of width a is illuminated by white light. The first minimum for red light (λ = 6500 Å) will fall at θ = 30° when a will be |
3250 Å $6.5× 10^{-4}cm$ 1.3 micron $2.6 × 10^{-4}cm$ |
1.3 micron |
Condition for 1st minimum is a Sin$\theta = \lambda$ a $\times \frac{1}{2} = 6500 A^o$ a = 13000 $A^o$ = 1.3 micron |
