A chemistry student is discussing several qualitative statements about photons with her lab partner. She claims that knowing only the wavelength of a photon is sufficient to predict its speed, frequency, and energy. Four specific photons are singled out for discussion:
• Photon A: a violet photon of wavelength 450 nm
• Photon B: a red photon of wavelength 650 nm
• Photon C: an ultraviolet photon of wavelength 300 nm
• Photon D: an infrared photon of wavelength 1000 nm
Respond to the prompts below to assess the accuracy and completeness of the student’s claims.
(a) Describe the relationship among the speed, wavelength, and frequency of electromagnetic radiation that travels in vacuum.
(b) Explain qualitatively how the energy of a photon changes when its wavelength is doubled while it remains in vacuum. No numerical calculations are required.
(c) Rank Photons A–D in order of increasing photon energy. Provide a brief justification for the position of each photon in your ordered list.