Question

1. rank the colors of the visible light spectrum from lowest frequency to highest frequency red orange yellow green blue indigo violet
2. rank the colors of the visible light spectrum from lowest energy per photon to highest energy per photon

for each problem:

• start which one of the equations above you will start with
• substitute your values with units.
• use your calculator to perform the math.
• give answer including units.

1. what is the wavelength of a wave having a frequency of 3.76 x 10¹⁴ hz?
2. what is the frequency of a 6.90x 10¹³ m wave?

Explanation:

7.

Step1: Recall frequency - color relationship

The frequency of visible light increases from red to violet.

Step1: Recall energy - frequency relationship

The energy of a photon is given by $E = h
u$ (where $h$ is Planck's constant and $
u$ is frequency). Since energy is directly proportional to frequency, the order of colors from lowest energy per photon to highest energy per photon is the same as the order from lowest frequency to highest frequency.

Step1: Use the wave - speed formula

The speed of light $c=\lambda
u$, where $c = 3.0\times10^{8}\ m/s$, $\lambda$ is wavelength and $
u$ is frequency. We want to find $\lambda$, so $\lambda=\frac{c}{
u}$.

Step2: Substitute values

Given $
u = 3.76\times 10^{14}\ Hz$, then $\lambda=\frac{3.0\times 10^{8}\ m/s}{3.76\times 10^{14}\ Hz}$.

Step3: Calculate

$\lambda=\frac{3.0\times 10^{8}}{3.76\times 10^{14}}\ m\approx7.98\times 10^{-7}\ m$

Answer:

red, orange, yellow, green, blue, indigo, violet

8.