1. Calculate the wavelength (in nm) of the red light emitted by a barcode scanner
that has a frequency of
4.62 x 1014 5-1.
649.4 nm

                       6.49 × 10⁻⁷ m    (or)     649 nm

Explanation:

Wavelength and Frequency are inversely proportional to each other. Greater the wavelength smaller the frequency and vice versa.

Solution:

The relation between wavelength and frequency is as follow,

                                             υ = c / λ

where

           υ = frequency = 4.62 × 10¹⁴ s⁻¹

           c = velocity of light = 3.0 × 10⁸ ms⁻¹

           λ = wavenumber = ??

Solving above equation for λ.

                                             λ  =  c / υ

Putting the given values,

           λ = 3.0 × 10⁸ ms⁻¹ / 4.62 × 10¹⁴ s⁻¹

Result:

           λ = 6.49 × 10⁻⁷ m    (or)     649 nm

it is reliable if two scientists recorded it