18. The author resolves the question of whether heat pumps run counter to the principle of energy conservation by
(A) carefully qualifying the meaning of that principle
(B) pointing out a factual error in the statement that gives rise to this question
(C) supplying additional relevant facts
(D) denying the relevance of that principle to heat pumps
(E) explaining that heat pumps can cool, as well as heat, room air
Quote:
Heat pumps circulate a fluid refrigerant that cycles alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature, low-pressure vapor, enters a compressor driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body of air. Now the refrigerant, as a high-pressure, cooled liquid, confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature of this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively.
Quote:
Now, if under certain conditions a heat pump puts out more thermal energy than it consumes in electrical energy, has the law of energy conservation been challenged? No, not even remotely: the additional input of thermal energy into the circulating refrigerant via the evaporator accounts for the difference in the energy equation.
The second paragraph , which is fascinating detailed, and the 4th one in which is explained that no contradictory information was given leads us to C. if you keep in mind the big picture and not get lost in those details, i.e. you see the perspective, then C is easy to pick. I did not even read more than two answer choices. C straight
----------------------------------------------------------------------19. It can be inferred from the passage that, in the course of a heating season, the heating capacity of a heat pump is greatest when
(A) heating is least essential
(B) electricity rates are lowest
(C) its compressor runs the fastest
(D) outdoor temperatures hold steady
(E) the heating demand surges
Here, then, lies a genuine drawback of heat pumps:
in extremely cold climates-where the most heat is needed-heat pumps are least able to supply enough heat.A is the answer. Notice how in this question at least a couple of answer choices could be ruled out even without reading the passage. Just for logic or the intention of the passage itself to explain something about heat pumps
----------------------------------------------------------------------20. If the author's assessment of the use of heat pumps is correct, which of the following best expresses the lesson that advertisers should learn from this case?
(A) Do not make exaggerated claims about the products you are trying to promote.
(B) Focus your advertising campaign on vague analogies and veiled implications instead of on facts.
(C) Do not use facts in your advertising that will strain the prospective client's ability to believe.
(D) Do not assume in your advertising that the prospective clients know even the most elementary scientific principles.
(E) Concentrate your advertising firmly on financially relevant issues such as price discounts and efficiency of operation.
Quote:
The use of heat pumps has been held back largely by skepticism about advertisers' claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation.
Basically the first passage tells us that heat pumps can achieve some sort of performance even though this would contradict the principle of energy. Now it seems already confused but what it is saying is that IF we go in-depth explanatory of this stuff we get lost. And after all the prospective client's ability is not interested in it. In the end, the customers will not buy a heat pump.
Notice how this question is pretty tricky
(A) Do not make exaggerated claims about the products you are trying to promote.
no advertising campaign or publicity or else surfaces from the passage
(B) Focus your advertising campaign on vague analogies and veiled implications instead of on facts.
Vague analogies. No on point
(C) Do not use facts in your advertising that will strain the prospective client's ability to believe.
Correct(D) Do not assume in your advertising that the prospective clients know even the most elementary scientific principles.
I do not see anything of knowledge related facts or we do understand something from the client's point of view.
(E) Concentrate your advertising firmly on financially relevant issues such as price discounts and efficiency of operation.
No financial issues emerged.
Regards
Apr 24
22 Jun 2019, 11:57
68% (02:44) correct
