SAT Subject Physics Practice Question 443: Answer and Explanation

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Question: 443

4. Which of the following occurs when light passes into a clear glass cube?

A. The light's wavelength changes.
B. The light's frequency changes.
C. The light's speed changes.
D. The light is polarized.
E. Both A and C

Correct Answer: E

Explanation:

The correct answer is (E). Light slows down when it enters a material that is more optically dense. Since the velocity is related to both the frequency and the wavelength by V = λf it follows that one of these quantities will change, too. Since the distance between the waves changes at the optical boundary, the wavelength also changes. The frequency remains unchanged.

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