Thermodynamic Devices: An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to 5.0° C. What is the high temperature needed to operate this refrigerator?
A. 61° C
B. 1395° C
C. 6° C
D. 30° C
Answer: A
You might also like to view...
If the Earth's period of rotation doubled, but the period of revolution stayed the same
a. the night would be twice as long. b. the night would be half as long. c. the year would be half as long. d. the year would be twice as long. e. the length of the day would be unchanged
Which of the following best explains why we can rule out the idea that planets are usually formed by near collisions between stars?
A) Stellar near collisions are far too rare to explain all the planets now known to orbit nearby stars. B) Studies of the trajectories of nearby stars relative to the Sun show that the Sun is not in danger of a near collision with any of them. C) A near collision might have created planets, but it could not have created moons, asteroids, or comets. D) A near collision should have left a trail of gas extending out behind the Sun, and we see no evidence of such a trail.
A ball is thrown straight up. It reaches its highest point and then falls back. Which of the following is the correct statement?
A. Throughout its motion, the ball's acceleration is zero B. At the highest point in its motion, the ball's acceleration is zero C. At the highest point in its motion, the ball's velocity and acceleration are zero D. At the highest point in its motion, the ball's velocity is zero E. Throughout its motion, the ball's velocity is zero
Which of the following wavelengths could NOT be present as a standing wave in a 2 m long organ pipe open at both ends?
a. 4 m b. 2 m c. 1 m d. 0.89 m e. 0.5 m