How long will it take if she stays in bed all day?
a. 2.41 hours
b. 57.8 hours
c. 37.7 hours
d. 0.228 hours
[Ques. 2] The number density of conduction electrons in a metal can be found from the density of the metal, the mass per mole M of the metal, the number of conduction electrons per metal atom, and Avogadro's number NA. If we assume one conduction electron per atom, which of the following gives the number density of conduction electrons for a given metal?
a. NA M
b. NA /M
c. NA M /
d. NA /M
[Ques. 3] A swimmer has a metabolic rate of 600 W. How many breaths per minute should the swimmer take if her lungs take in 0.50 L of air in each breath, and the percentage of oxygen in the air is 21?
a. 25.2
b. 120
c. 33.5
d. 17.1
[Ques. 4] Wire A and Wire B are each carrying the same current. If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdA in Wire A compare to that in in Wire B?
a. vdA = vdB
b. vdA = 2 vdB
c. vdA = vdB /2
d. vdA = vdB /4
[Ques. 5] If you roll a pair of dice, what is the total number of ways in which you can obtain a 3?
a. 2
b. 3
c. 4
d. 5
[Ques. 6] If the current in a wire is tripled, what effect does this have on the electron drift velocity in the wire?
a. It stays the same.
b. It triples.
c. It decreases by a factor of three.
d. It increases by a factor of nine.
[Ques. 7] Two cars, each of mass 2 200 kg and traveling at 14.0 m/s, undergo a head-on completely inelastic collision. What is the change in entropy of the Universe which results from this collision? Assume the ambient temperature is 20.0C.
a. 1.47E+3 J/K
b. 2.2E+4 J/K
c. 7.35E+2 J/K
d. 6.2E+5 J/K
[Ques. 8] A 300-Ah battery can deliver how many coulombs starting from a full charge?
a. 4.8 103 b. 4.3 104
c. 7.2 105 d. 1.1 106
[Ques. 9] Two objects, A and B, are placed in thermal contact. The entropy of object A decreases. What can be said about the relationship between the temperatures of the two objects?
a. TA < TB
b. TA > TB
c. TA = TB
d. not enough information to say
[Ques. 10] A lightbulb drawing a current of 0.60 A is run for 2.0 hours. How many electrons pass through the bulb during this process?
a. 2.7 1022 b. 1.4 1019
c. 5.4 1025 d. 4.3 103
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