Question

The path differnce between two interferring waves at a point on screen is`171.5`times the wavelength.if the path diffrence is`00129cm`Find the wavelenghth.
A. `6000xx10^(-10)cm`
B. `6000A^(@)`
C. `6000xx10^(-8)mm`
D. None

Answer 1

Answer:
Path differnce= `171.5 lambda`
`=(343)/(2) lambda`=odd mulitple of half wavelength
It means dark finge is observed
According the question
`0.01029=(343)/(2)lambda`
`rArr lambda=(0.01029xx2)/(343)=6xx10^(-5)cm rArr lambda rArr =6000A^(@)`