In a biprism experiment, the distance between 4th and 13th bright band on the same side is ' y ' when light of wavelength 6000 Å is used. For a light of wavelength ' λ ' the distance between 6th and 16th bright band on the same side is again ' y '. The value of ' λ ' in Å units is (a) 6500 (b) 6300 (c) 5400 (d) 4800

Answer: (c). Distance between m th and n th bright bands = (n-m)β, with β ∝ λ. 9β₁ = y and 10β₂ = y ⇒ 9 × 6000 = 10λ. λ = 5400 Å. So the answer is (c) 5400.

In a biprism experiment, the distance between 4th and 13th bright… | MHT CET 2026 (20 Apr, Shift 1)

Q3MHT CET 2026 · 20 APR · SHIFT 1Medium

Biprism, Thin Films & Other Devices

In a biprism experiment, the distance between $4^{th}$ and $13^{th}$ bright band on the same side is ' $y$ ' when light of wavelength $6000$ Å is used. For a light of wavelength ' $\lambda$ ' the distance between $6^{th}$ and $16^{th}$ bright band on the same side is again ' $y$ '. The value of ' $\lambda$ ' in Å units is

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Answer: (c)

Distance between $m$ th and $n$ th bright bands $= (n-m)\beta$ , with $\beta \propto \lambda$ .
$9\beta_1 = y$ and $10\beta_2 = y \Rightarrow 9 \times 6000 = 10\lambda$ .
$\lambda = 5400$ Å. So the answer is (c) 5400.

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