 
Summary: Physics 181 Final Exam Practice Fall 2011
Dr. S.G. Alexander Miami University
Multiple Choice. Choose the one alternative that BEST completes the statement or answers the question, and mark your
scan sheet. Only the scan sheet will be graded. The correct answers are A, A, C, B, C, C
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) A standing wave is oscillating at 690 Hz on a string, as shown in the figure. What is the wave speed?
A) 280 m/s B) 140 m/s C) 410 m/s D) 210 m/s
2) A laser emits a pulse of light that lasts 10 ns. The light has a wavelength of 690 nm, and each pulse has an
energy of 950 mJ. How many photons are emitted in each pulse?
A) 3.3 × 1018 B) 5.2 × 1037 C) 4.2 × 1027 D) 6.1 × 1043
3) Calculate the orbital Bohr radius of the n = 3 excited state in a hydrogen atom.
A) 0.548 nm B) 0.381 nm C) 0.476 nm D) 0.159 nm
4) Light excites atomic hydrogen from its lowest level to the n = 4 level. What is the energy of the light?
A) 65.1 eV B) 14.5 eV C) 97.3 eV D) 34.1 eV
5) A graph of (x) 2 for an electron is shown in the figure. What is the probability that the electron is located
between x = 0.8 nm and x = 2.0 nm?
A) 0.36 B) 0.090 C) 0.18 D) 0.27
6) An electron is confined to an infinite square well of width 0.887 nm. Find the energy difference in eV between
the ground state and the first excited state of this system.
A) 1.72 eV B) 0.48 eV C) 1.44 eV D) 0.57 eV
