Physics quiz question: Wien displacement constant units

Physics 205A Quiz 1, fall semester 2016
Cuesta College, San Luis Obispo, CA

The Wien displacement constant b is given by the expression[*]:

b = h·c/k.

The Planck constant h is measured in units of kg·m²·s^–1, the speed of light c is measured in units of m·s^–1, and the Boltzmann constant k is measured in units of K^–1·kg·m²·s^–2. The units for the Wien displacement constant b are:
(A) K·m.
(B) K^–1·s^–1.
(C) K·kg·m^–1.
(D) K^–1·m⁴·s^–4.

[*] wki.pe/Physical_constant#Physico-chemical_constants.

Correct answer (highlight to unhide): (A)

Starting with the expression for the Wien displacement constant b:

b = h·c/k,

and replacing the quantities in the equation with their K, kg, m and s units, the units of b are:

b = (kg·m²·s^–1)·(m·s^–1)/(K^–1·kg·m²·s^–2),

b = (kg·m³·s^–2)/(K^–1·kg·m²·s^–2),

b = K·m.

Sections 70854, 70855, 73320
Exam code: quiz01bIR6
(A) : 53 students
(B) : 2 students
(C) : 0 students
(D) : 2 students

Success level: 93%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.15