The wave number of two waves are ` 2.5 xx 10^(6)`/ metre and ` 2 xx 10^(6)`/metre. What is the difference between their wavelengths ?

Options

A. `5000Å`
B. `4000Å`
C. `2000Å`
D. `1000Å`

Answer

D

Explanation

Wavelength `=(1)/("Wave number ")`
`:. lambda_1=(1)/(2.5 xx 10^(6))=4 xx 10^(-7)` m
`and lambda_2=(1)/(2 xx 10^(6))= 5 xx 10^(-7) m`
`:. lambda_2- lambda_1=10^(-7)m=10^(-7) xx 10^(10)=10^(3)Å`