Question

The path difference produced by two waves is 3.75 `mu`m and the wavelength is 5000 Å. The point is
A. uncertain
B. dark
C. partially bright
D. bright

Answer 1

Correct Answer - B
Here, path difference `Delta x=3.75 mu m=3.75 xx 10^(-6)m`
Wavelength `lambda=5000"Å"=5xx10^(-7)m`
`(Delta x)/(lambda)=(3.75xx10^(-6))/(5xx10^(-7))=(37.5)/(5)=7.5`
`therefore Delta x=7.5 lambda`
Here, `Delta x` is odd multiple of `lambda`, so point is dark.