The frequency of light beam A is twice that of light beam B.The ratio E_A/E_B of photon energies is: A)1/2 B)1/4 C)1 D)2 E)4

Question

Quizplus · Accepted Answer

The energy of a photon is directly proportional to its frequency. Thus, the energy of photon A is twice that of photon B (since frequency of A is twice that of B). Let E(A) be the energy of photon A and E(B) be the energy of photon B. Then, E(A) = 2E(B) The ratio of their energies can be written as: (E(A) / E(B)) = 2 Thus, the ratio of their energies is 2 or 1:2. Now, the ratio of any two quantities with the same units can be simplified. For example, the ratio of the heights of two buildings is 20:30 which simplifies to 2:3. Similarly, the ratio of photon energies can be simplified as: (E(A) / E(B)) = 2 => (E(A) / E(B)) / 2 = 1 => E(A) / 2E(B) = 1 => E(A) / E(B) = 2 Therefore, the ratio of photon energies E_A/E_B is 2 or 2:1. Thus, the answer is D) 2.

The Frequency of Light Beam a Is Twice That of Light