Question

A sodium street light gives off yellow light that has a wavelength of $600$nm. Then

• A. Frequency of this light is $7\times {10}^{14}{s}^{-1}$
• B. frequency of this light is $5\times {10}^{14}{s}^{-1}$
• C. wave number if the light is $3\times {10}^6{m}^{-1}$
• D. energy of the proton is approximately $2.07Ve$

Answer 1

The correct option is B frequency of this light is $5\times {10}^{14}{s}^{-1}$

Wave length of light= $600nm=600\times {10}^{-9}M$

Frequency= $\frac{Velocityoflight}{Wavelength}$

$=\frac{3\times {10}^8}{6000\times {10}^{-9}}=\frac{13}{26}\times {10}^{15}\Rightarrow \frac{1}{2}\times {10}^{15}{s}^{-1}$

Wave number= $\frac{1}{Wavelength}=\frac{1}{600\times {10}^{-9}}\Rightarrow \frac{1}{6}\times {10}^7$