Question

Path difference between two wavefronts emitted from coherent sources is $2.1 \, μm.$ Phase difference between the wavefronts at that point is $7.692\pi $ . Wavelength of light emitted by source will be

• A. $5385 \, Å$
• B. $5600 \, Å$
• C. $5460 \, Å$
• D. $5892 \, Å$

Answer 1

Answer: (C)

Phase difference, $\phi=\frac{2 \pi x}{\lambda }$ or $\lambda =\frac{2 \pi x}{\phi}$
$=2\times \pi \times \frac{2.1 \times 10^{- 6}}{7.692 \, \pi }=5460\times 10^{- 10} \, m$