During each cycle of operation a refrigerator absorbs 45 cal from the freezer compartment and expels 85 cal to the room. If one cycle occurs every 8.0 s, how many minutes will it take to freeze 500 g of water, initially at 0°C? (Lv = 80 cal/g)
a. 800 min
c. 120 min
b. 4400 min
d. 150 min
C
You might also like to view...
In the respiration reaction
A) carbon combines with such biological molecules as DNA. B) oxygen combines with the carbon in such biological molecules as glucose. C) CO2 combines with the carbon in such biological molecules as glucose. D) CO2 combines with H2O. E) oxygen combines with such biological molecules as DNA.
An O-star has a hotter surface temperature than the Sun. Therefore, compared to the Sun,
A) its emission peaks in the infrared part of the spectrum. B) its emission peaks in the blue part of the spectrum. C) it emits at about the same wavelengths as the Sun (similar peak) but it is much brighter. D) it emits at about the same wavelengths as the Sun (similar peak) but it is much fainter.
The combination of two separated point charges of opposite sign but equal magnitude is called an electric:
a. monopole. b. dipole. c. quadrapole. d. magnapole.
Identify the FALSE statement:
A fifth-generation star would have a greater proportion of heavier elements than a second-generation star. The elements of any person's body were once star matter; therefore we are all literally made of stardust. Our Universe is so old there are no first-generation stars left in it. Dense regions of a nebula pull in surrounding material and therefore grow in mass and density and rotate faster. An accretionary disk eventually grows hot and massive enough to become a protostar, then a star.