A spaceship traveling at constant speed passes by Earth and later passes by Mars. In which frame of reference is the amount of time separating these two events the proper time?
A) the Earth frame of reference
B) the Mars frame of reference
C) the spaceship frame of reference
D) any inertial frame of reference
E) any frame of reference, inertial or not
C
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Two plane mirrors are joined at a right angle. A beam of light is shone on one of the mirrors at an angle of incidence of 22 degrees, such that the reflected ray strikes the other mirror. What is the angle of incidence for the beam that strikes the second mirror?
A. 
B. 
C. 
D. 
Series Resonance: A series ac circuit has a resonance frequency of 9.0 kHz. If the inductor in the circuit has a value of 2.0 H, and the resistance is 75 ?, what is the capacitance of the circuit?
A. 0.16 pF B. 156 pF C. 6.2 pF D. 17.7 pF
In the absence of the greenhouse effect, the water on the surface of Earth would
a. escape into outer space. b. remain in liquid form. c. vaporize and form clouds in the atmosphere. d. freeze. e. be absorbed into rocks.
A circuit contains two inductors of 6.0-mH inductance in parallel placed in series with an inductor of 8.0-mH inductance. After one of the 6.0-mH inductors burns out, the repairman wants to replace all three inductors with one inductor of equivalent inductance. Assuming inductors combine in series and parallel the same way resistors do, what inductance should he use?
a. 3.0 mH b. 3.4 mH c. 4.8 mH d. 11 mH e. 20 mH