Suppose that the Department of Energy develops a new reversible engine that has a coefficient of performance (COP) of 4.0 when operated as a refrigerator and a COP of 5.0 when operated as a heat pump
What is its thermal efficiency when operated as a heat engine doing work? A) 10%
B) 20%
C) 25%
D) 45%
E) 80%
B
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Does a baseball have large quantum uncertainties, or small ones?
A) Small, because the baseball has such a large mass. B) Large, because the baseball has such a large mass. C) Large, because the baseball has such a small mass. D) Small, because the baseball has such a small mass. E) It's impossible to tell unless we know how fast the baseball is moving.
A 10-kg rock and a 20-kg rock are thrown upward with the same initial speed v0 and there is no air. If the 10-kg rock reaches a maximum height h, what maximum height will the 20-kg ball reach?
A) h/4 B) h/2 C) h D) 2h E) 4h
The circuit below shows three resistors in series. R3 > R2 > R1. The resistors are all made of the same wire with the same diameter but have different lengths. Rank the magnitudes of the electric fields in the resistors from least to greatest
a.
E3 < E2 < E1.
b.
E2 < E1 = E3.
c.
E1 = E2 = E3.
d.
E1 = E3 < E2.
e.
E1 < E2 < E3.
How will using wet ice (some water at 0°C is added along with the ice) affect the experimental value for the latent heat of fusion of ice? Explain