Wavelengths question

Question

Consider two photons: one with a frequency of 5 Hz and one with a frequency of 15 Hz. Which of the following describes their respective wavelengths?



A. The 5 Hz photon’s wavelength is 9 times longer than the 15 Hz photon’s wavelength. 

B.The 5 Hz photon’s wavelength is 3 times longer than the 15 Hz photon’s wavelength. 

C. The two photons will have the same wavelength.

D. The 15 Hz photon’s wavelength is 3 times longer than the 5 Hz photon’s wavelength. o The 15 Hz photon’s wavelength is 9 times longer than the 5 Hz photon’s wavelength.

Answer 1

The formula we need to look at is λ = v/f. This formula says that wavelength and frequency are inversely proportional (so that higher frequencies mean lower wavelengths.)

For the 5 Hz wave, its wavelength would be v/5 or (1/5)v.

For the 15 Hz wave, its wavelength would be v/15 or (1/15)v.

Since 1/5 is 3 times bigger than 1/15, the answer would be B.