Which of the following best describes the image from a plane mirror?
a. virtual and magnification equal to one
b. real and magnification equal to one
c. real and magnification less than one
d. virtual and magnification greater than one
[Ques. 2] A waterfall is 70 m high. What is the increase in water temperature at the bottom of the falls if all the initial potential energy goes into heating the water? (g = 9.8 m/s2, cw = 4186 J/kgC)
a. 0.16C
c. 0.69C
b. 0.34C
d. 1.04C
[Ques. 3] You stand three feet away from a plane mirror. How far is it from you to your image?
a. 4.0 ft
c. 2.0 ft
b. 6.0 ft
d. 3.0 ft
[Ques. 4] A 0.2-kg aluminum plate, initially at 20C, slides down a 10-m long surface, inclined at a 30 angle to the horizontal. The force of kinetic friction exactly balances the component of gravity down the plane so that the plate, once started, glides down at constant velocity. If 90 of the mechanical energy of the system is absorbed by the aluminum, what is its temperature increase at the bottom of the incline? (Specific heat for aluminum is 900 J/kg C.)
a. 0.16C
c. 0.05C
b. 0.07C
d. 0.03C
[Ques. 5] Two mirrors are joined together along a common side, the planes of the mirrors separated by the angle q. If the joined mirrors can be used as a retroreflector when a beam of light strikes both surfaces (one after the other), what is the value of q?
a. 90
c. 45
b. 135
d. 30
[Ques. 6] A solar heated house loses about 7.4 107 cal through its outer surfaces on a typical 24-hour winter day. What mass of storage rock is needed to provide this amount of heat if it is brought up to initial temperature of 62C by the solar collectors, and the house is maintained at 20C? (Specific heat of rock is 0.21 cal/g C.)
a. 160 kg
c. 6100 kg
b. 1200 kg
d. 8400 kg
[Ques. 7] When light reflects and produces a clear image, this reflection is referred to as:
a. retroreflection.
c. diffuse reflection.
b. specular reflection.
d. double reflection.
[Ques. 8] A swimming pool heater has to be able to raise the temperature of the 30,000 gallons of water in the pool by 10.0C. How many kilowatt-hours of energy are required? (One gallon of water has a mass of approximately 3.79 kg and the specific heat of water is 4186 J/kg C.)
a. 1960 kWh
c. 1130 kWh
b. 1320 kWh
d. 216 kWh
[Ques. 9] When viewing your image in a hand-held mirror, if you move the mirror away at a speed v, the image appears to:
a. also move away at v.
c. move away at 2v.
b. move away at v/2.
d. not move.
[Ques. 10] A 3.00 g lead bullet is traveling at a speed of 300 m/s when it embeds in a wood post. If we assume that half of the resultant heat energy generated remains with the bullet, what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg C, 1 kcal = 4186 J)
a. 113C
c. 176C
b. 137C
d. 259C
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