Sample 1Medium
A sketch of Young's double-slit experiment shows two slits 0.5 mm apart, lit by light of wavelength 600 nm, with a screen 1 m away on which bright and dark fringes are drawn. What is the fringe width?
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The answer is B.
β = λD/d = (600 × 10⁻⁹ × 1)/(0.5 × 10⁻³) = 1.2 × 10⁻³ m = 1.2 mm.
- A.
0.12 mm is ten times too small; it misplaces the power of ten.
- C.
12 mm is ten times too large.
- D.
0.3 mm does not follow from β = λD/d with the values given.
NCERT: Class 12 Physics, Chapter 10