CK-12-Physics - Intermediate

http://www.ck12.org Chapter 21. Physical Optics

also 180◦. Thus, the net effect amounts to no phase change, and we can use the equation for constructive interference
2 d=

(

m+^12

)

λ. Recall, however, that we must use the wavelength of light in the oil and, therefore

λn=

λair

noil

2 d=mλn→ 2 d=m

λ

n

→d=m

λ

2 n

= ( 1 )

525 nm

2 ( 1. 20 )

= 218 .8 nm=219 nm