Question

The rays of the Sun that cause tanning and burning are in the ultraviolet portion of the electromagnetic spectrum. These rays are categorized by wavelength: So-called UV-A radiation has wavelengths in the range of 320-380 nm, whereas UV-B radiation has wavelengths in the range of 290-320 nm.

Part A

Calculate the frequency of light that has a wavelength of 345 nm .

ν =

  s−1  

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Part B

Calculate the energy of a mole of 345 − nm photons.

E =

  kJ/mol  

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Part C

Which are more energetic, photons of UV-A radiation or photons of UV-B radiation?

photons of UV-A radiation

photons of UV-B radiation

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Part D

The UV-B radiation from the Sun is considered a greater cause of sunburn in humans than is UV-A radiation. Is this observation consistent with your answer to part (c) ?

yes

no

Answer 1