A point is situated at 6.5 cm and 6.65 cm from two coherent sources. Find the nature of illumination at the point if wavelength of light is 5000 Å.

Options

A. Bright
B. Dark
C. Low bright
D. Low dark

Answer

A

Explanation

It is given that
`x_(1)=6.5 cm and x_(2)=6.65cm`
`lamda=5000`Å`=5xx10^(-7)m`
`therefore`Path difference, `Deltax=x_(2)-x_(1)`
`=6.65-6.5`
`=0.15cm=15xx10^(-4)m`
`therefore("Path difference "(Deltax))/(lamda)=(15xx10^(-4))/(5xx10^(-7))`
`=3xx10^(-3)`
or `Deltax=3xx10^(3)lamda=3000lamda`
`=(6000lamda)/(2)=("even")(lamda)/(2)`
`therefore`Point is bright.