Which of the following types of ultraviolet radiation is generally considered…
2017
Which of the following types of ultraviolet radiation is generally considered the most damaging?
- A.
UV-A
- B.
UV-B
- C.
UV-C
- D.
None of the above
Attempted by 8 students.
Show answer & explanation
Correct answer: C
Concept
Photon energy increases as wavelength decreases: E = hc/lambda. Therefore, shorter-wavelength ultraviolet radiation carries more energy per photon and can cause greater biological damage.
The ultraviolet spectrum is commonly divided into UV-A, UV-B, and UV-C bands in decreasing order of wavelength.
Application
Among the listed bands, UV-C has the shortest wavelength and highest photon energy. It is strongly absorbed by atmospheric oxygen and ozone, but when exposure occurs it is the most damaging to biological material.
Contrast
UV-A has the longest wavelength and lowest photon energy of the three bands; it penetrates skin deeply but is not the most energetic band.
UV-B causes sunburn and contributes substantially to skin damage from sunlight, yet its photons carry less energy than UV-C photons.
None of the above asserts that no listed band answers the question; that assertion is inconsistent with the wavelength-energy comparison above.
Cross-check
The wavelength-energy relationship independently confirms the ranking: the shortest-wavelength band has the highest photon energy.
Result
Therefore, UV-C is generally considered the most damaging ultraviolet radiation.