Question

Now, if $600nm$ light is replaced by white light of range $400$ to $800nm$, find the wavelength of the light that forms maxima exactly at point $O$.

• A. $650nm$, $433.3nm$
• B. $550nm$, $750nm$
• C. $450nm$, $645.3nm$
• D. $375nm$, $525.3nm$

Answer 1

The correct option is A $650nm$, $433.3nm$

Equating Path Difference due to Slab to Multiple of Wavelenght for Constructive interference:

$t\times ({\mu }_r-1)=n\lambda$

For Different values of n, we get $\lambda$ in 800-400 nm

${\lambda }_1=650nm;{\lambda }_2=433.3nm$