-- There is nothing on the list of choices that you provided that has no mass.
-- There are no "things" that have no mass. Every sample of a liquid, a gas,
or a solid has mass, even if it's only an atom or two.
I think the only possible items you could name that have no mass would be
spiritual, conceptual, or sensory ones, like maybe ...
-- idea
-- conviction
-- belief
-- concept
-- image
-- sound
-- illusion
-- impression
-- agreement
-- inclination
-- tendency
-- sparkle
-- tingle
-- pain
Things like that.
Answer:
<em>Heat of the reservoir is 461.38 K or 188.1 °C</em>
<em>The heating load is 18.705 kW</em>
Explanation:
COP = 8.7
working temperature
= 248 °C = 248 + 273.3 = 521.3 K
work power W = 2.15 kW
reservoir temperature
= ?
heating load Q = ?
We know that
COP = Q/W
Q = COP x W = 8.7 x 2.15 = <em>18.705 kW</em>
Also,
COP =
= 
8.7 = 
4535.31 - 8.7
= 521.3
4535.31 - 521.3 = 8.7
4014.01 = 8.7
= 4014.01/8.7 = <em>461.38 K</em>
or 461.38 -273.3 = <em>188.1 °C</em>
I hope you find the answer :)