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Question: Answered & Verified by Expert
A slit of width a is illuminated by white light. The first minimum for red light λ=6500  will fall at θ=30o, when a is
PhysicsWave OpticsNEET
Options:
  • A 3250 
  • B 6.5×10-4 cm
  • C 1.3 μm
  • D 2.6×10-4 cm
Solution:
1312 Upvotes Verified Answer
The correct answer is: 1.3 μm
sinθ=λa

sin30o=6500a

  12=6500a

a=2×6500 

a=2×6500×10-10 m

     a=1.3×10-6 m

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