Question

Find the range of frequency of light that is visible to an average human being $(400nm<\lambda <700nm)$

Answer 1

We know that speed of light is $3\times {10}^{8}m/s$ and $v=f\lambda$

Lower limit of frequency range of visible light will be corresponding to $\lambda =700nm=7\times {10}^{-7}$

$f_L=\frac{3\times {10}^8}{7\times {10}^{-7}}=(4.285\times {10}^{14})Hz$

And, upper limit of frequency range of visible light will be corresponding to $\lambda =400nm=4\times {10}^{-7}$

$f_U=\frac{3\times {10}^8}{4\times {10}^{-7}}=(7.5\times {10}^{14})Hz$

So,range of frequency of light that is visible to an average human being is $(4.285\times {10}^{14})Hz$ to $(7.5\times {10}^{14})Hz$