Physics quiz question: wavelength from air into amber

Physics 205B Quiz 1, Spring Semester 2011
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 22.19(a).

Green laser light of wavelength 532 nm in air passes into amber (index of refraction 1.546). What is the wavelength of the light inside the amber?
(A) 290 nm.
(B) 344 nm.
(C) 532 nm.
(D) 822 nm.

Correct answer: (B)

The frequency of light is the same in either medium, where n_1 = n_air = 1.000, and n_2 = n_amber = 1.546 such that:

f_ 1 = f_2,

v_1/lambda_1 = v_2/lambda_2,

lambda_2 = lambda_1*(v_2/v_1) = lambda_1*((c/n_2)/(c/n_1)) = lambda_1*(n_1/n_2) = (532 nm)*(1.000/1.546) = 344 nm.

Response (A) = (n_air - n_amber)*lambda_air; response (D) is lambda_air*n_amber.

Student responses
Section 70856
(A) : 0 students
(B) : 5 students
(C) : 3 students
(D) : 0 students

Success level: 63%
Discrimination index (Aubrecht & Aubrecht, 1983): 1.