Question

Find the frequency range of visible light, given that it encompasses wavelengths from 380 nm to 760 nm.

• A. $3.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$
• B. $3.95\times {10}^{17}{\text{s}}^{-1}\to 7.89\times {10}^{17}{\text{s}}^{-1}$
• C. $2.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$
• D. $2.95\times {10}^{17}{\text{s}}^{-1}\to 7.89\times {10}^{17}{\text{s}}^{-1}$

Answer 1

The correct option is A $3.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$

We know,
$c=\lambda v$
where $c=\text{velocity of light}$
$\lambda =\text{wavelength of light}$
$v=\text{frequency of light}$
or $v=\frac{c}{\lambda }$
So, lower the value of wavelength, higher is the frequency.
Hence the frequency range will be:
$v=\frac{3\times {10}^8}{760\times {10}^{-9}}\to v=\frac{3\times {10}^8}{380\times {10}^{-9}}$

$3.95\times {10}^{14}{\text{s}}^{-1}\to 7.89\times {10}^{14}{\text{s}}^{-1}$