Question

One of the emission lines that provides the green color in fireworks, which com s from barium salts, has a wavelength of 505nm. a. Determine the frequency of this green line. b. Determine the energy associated with this green line. c. Arrange the visible spectrum in order of increasing wavelength, frequency, and energy

Answer 1

Explanation:

(a)

The relation between frequency and wavelength is shown below as:

$c=frequency\times Wavelength$

c is the speed of light having value $3\times 10^8\ m/s$

Given, Wavelength = 505 nm

Also, 1 m = $10^{-9}$ nm

So,  

Wavelength = $505\times 10^{-9}$ m

Thus, Frequency is:

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

$Frequency=\frac{3\times 10^8}{505\times 10^{-9}}\ Hz$

$Frequency=5.94\times 10^{14}\ Hz$

(b)

Also, $E=\frac {h\times c}{\lambda}$

Where,  

h is Plank's constant having value $6.626\times 10^{-34}\ Js$

c is the speed of light having value $3\times 10^8\ m/s$

So,

$E=\frac{6.626\times 10^{-34}\times 3\times 10^8}{505\times 10^{-9}}\ J$

$E=\frac{10^{-26}\times \:19.878}{10^{-9}\times \:505}\ J$

$E=3.94\times 10^{-19}\ J$

(c)

Electromagnetic spectrum is range of the frequencies and their respective wavelengths of the various type of the electromagnetic radiation.

In order of the increasing frequency and the photon energy and the decreasing wavelength the spectrum are:  

Red , Orange, Yellow, Green, Blue, Indigo, Violet

Increasing wavelength is the opposite trend. Thus, The longest visible wavelength is red and the shortest is violet.