Interference fringes were observed in an interference chamber, where air was present.now, the chamber is evacuated and without disturbing the arrangement, intererence pattern is again obserbed. A careful observer will see

Options

A. no interference
B. uniform illumination
C. an interference patternn with a slight increase in the width of the fringes
D. an interference pattern with a slight decrease in the width of the fringes

Answer

C

Explanation

`lamda=(Xd)/(D) " "therefore X=(lamdaD)/(d)`
`lamda_("vacuum")gt lamda_(air)`
9air is a denser medium as compared to vacuum)
`therefore ` As `X prop lamda`, the fringe width will increase.