The question is missing. Here is the complete question.
One light beam has wavelength, [tex]\lambda_{1}[/tex], and frequency, f₁. Another light beam has wavelength, [tex]\lambda_{2}[/tex], and frequency, f₂. Write a proportion that shows how the ratio of the wavelengths of these two light beams is related to the ratio of the frequencies.
Answer: [tex]\frac{f_{1}}{f_{2}} =\frac{\lambda_{2}}{\lambda_{1}}[/tex]
Explanation: In vacuum, eletromagnetic waves travels at a constant speed called "speed of light", whose symbol is [c] and magnitude is 3x10⁸m/s.
Speed of light, frequency and wavelength are related by the formula:
[tex]c=\lambda.f[/tex]
So, if one light beam has wavelength and frequency, [tex]\lambda_{1}[/tex] and f₁, respectively, the second beam has wavelength [tex]\lambda_{2}[/tex] and frequency f₂ and both travel at speed of light:
[tex]\lambda_{1}f_{1}=\lambda_{2}f_{2}[/tex]
[tex]\frac{f_{1}}{f_{2}}=\frac{\lambda_{2}}{\lambda_{1}}[/tex]
Then, the ratio that shows the relation between frequencies and wavelengths of these light beams is [tex]\frac{f_{1}}{f_{2}}=\frac{\lambda_{2}}{\lambda_{1}}[/tex]