A thin film of soapy water, n = 1.37, is held vertical. Light of wavelength 600 nm is reflected from the film and horizontal dark lines appear. What is the thinnest soap film for which a bright band will occur?
A. 150 nm
B. 109 nm
C. 90.0 nm
D. 438 nm
E. 219 nm
B. 109 nm
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Thermal Expansion: The coefficient of linear expansion of steel is 12 × 10-6 K-1. What is the change in length of a 25-m steel bridge span when it undergoes a temperature change of 40 K from winter to summer?
A. 1.2 cm B. 1.4 cm C. 1.6 cm D. 1.8 cm E. 2.0 cm
Nuclear Binding Energy: The neutral helium atom, 
He, has a mass of 4.002603 u, a neutron has a mass of 1.008665 u, a proton has a mass of 1.007277 u, and a neutral hydrogen atom has a mass of 1.007825 u. What is the binding energy of the 
He nucleus? (1 u = 931.5 MeV/c2)
A. 20.5 MeV B. 22.4 MeV C. 27.3 MeV D. 28.3 MeV E. 23.4 MeV
A 50-kg air conditioner is placed on top of a concrete pad with a cross-sectional area of 3.0 m2 and 20 cm thick. What is the change in thickness of the pad? Young's modulus for concrete is 2.3 × 1010 N/m2
A) 1.4 × 10-9 m B) 2.8 × 10-9 m C) 1.4 × 10-8 m D) 1.4 × 10-7 m E) 2.8 × 10-8 m
The maximum theoretical thermodynamic efficiency of a heat engine operating between hot and cold reservoirs is a function of which of the following?
a. hot reservoir temperature only b. cold reservoir temperature only c. both hot and cold reservoir temperatures d. None of the above choices are valid.