Question

The path difference between two wavefronts emitted by coherent sources of wavelength 5460 $\stackrel{o}{A}$ is 2.1 micron. The phase difference between the wavefronts at that point is

• A. 7.962
• B. 7.962 $\pi$
• C. $\frac{7.962}{\pi }$
• D. $\frac{7.962}{3\pi }$

Answer 1

Answer: (B)

7.962 $\pi$

Phase diff. = $\frac{2\pi x}{\lambda }$
Path difference = $\frac{2\pi \times 2.1\times {10}^{-6}}{5460\times {10}^{-10}}$ = 7.692 $\pi$ radian.