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.

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.

How can we describe the Raman effect? (A) As inelastic scattering of photons on molecules. (B) As elastic scattering of photons on molecules. (C) As frequency modulation of a carrier wave. (D) A and C. (E) B and C.

How can we describe the Raman effect? (A) As inelastic scattering of photons on molecules. (B) As elastic scattering of photons on molecules. (C) As frequency modulation of a carrier wave. (D) A and C. (E) B and C.