Physics 9702 · AS & A Level · Interference

Interference — practice question

Monochromatic light is directed at two very narrow slits separated by a distance of $0.10\,\text{mm}$. On a screen $2.0\,\text{m}$ away, an alternating pattern of bright and dark fringes is formed. The spacing between neighbouring bright fringes is $8.0\,\text{mm}$. What path difference between the waves from the two slits corresponds to the second-order dark fringe?

  • A$2.0 \times 10^{-7}\,\text{m}$
  • B$4.0 \times 10^{-7}\,\text{m}$
  • C$6.0 \times 10^{-7}\,\text{m}$
  • D$8.0 \times 10^{-7}\,\text{m}$

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