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Why is the sky blue?

Why is the sky blue? (A) Because the oxygen in air is absorbing reddish light, so the remaining light has a bluish tinge. (B) Because blue light is refracted more strongly than red light.

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Why is the sky blue?

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  1. Why is the sky blue? (A) Because the oxygen in air is absorbing reddish light, so the remaining light has a bluish tinge. (B) Because blue light is refracted more strongly than red light. (C) Because the probability for light scattering increases with the light frequency to the 4th power. (D) Because blue light is diffracted more strongly than red light. (E) Because the water vapor in the air absorbs red light (vibrational overtones), so the remaining light has a bluish tinge.

  2. Why is the sky blue? (A) Because the oxygen in air is absorbing reddish light, so the remaining light has a bluish tinge. Baloney (B) Because blue light is refracted more strongly than red light. while blue light is indeed refracted more strongly, that doesn’t make the sky blue. (C) Because the probability for light scattering increases with the light frequency to the 4th power. CORRECT! This results in blue light scattered more strongly. When we look at the sky, we see the scattered light. (D) Because blue light is diffracted more strongly than red light.Wrong ... it’s the other way around. (E) Because the water vapor in the air absorbs red light (vibrational overtones), so the remaining light has a bluish tinge. That is what gives water a bluish color, but not the sky.

  3. Which of the processes indicated below will be observed? Energy Virtual Energy Level hn0 hn0+Evib hn0 hn0-Evib hn0 hn0 • I II III • Only process I. • Processes I and II. • All three processes. 1st excited vibrational state ground state { DE = Evib

  4. Which of the processes indicated below will be observed? Energy Virtual Energy Level hn0 hn0+Evib hn0 hn0-Evib hn0 hn0 • I II III • Only process I. • Processes I and II. • All three processes. 1st excited vibrational state ground state { DE = Evib

  5. Recall the selection rules for purely rotational microwave spectra: DJ = ±1. This came from angular momentum conservation (a photon has spin angular momentum ħ). In Raman scattering, one photon comes in and one photon goes out. What do you think are the selection rules for rotational Raman transitions? (A) DJ = ±1 (B) DJ = 0, ±1, ±2 (C) DJ = 0, ±2 (D) DJ = 0

  6. Recall the selection rules for purely rotational microwave spectra: DJ = ±1. This came from angular momentum conservation (a photon has spin angular momentum ħ). In Raman scattering, one photon comes in and one photon goes out. What do you think are the selection rules for rotational Raman transitions? (A) DJ = ±1 (B) DJ = 0, ±1, ±2 (C) DJ = 0, ±2 * (D) DJ = 0 * makes sense, because a photon comes in and transfers one unit of ħ to the molecule, and one photon comes out again, which again has one unit of ħ. If the incoming and outgoing photons have the same spin, DJ = 0. If they have oppositespins, DJ = ±2.

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