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# Electrical engineers have developed an energy-efficient type of light

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Joined: 02 Sep 2009
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Electrical engineers have developed an energy-efficient type of light  [#permalink]

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05 Jan 2019, 06:35
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Difficulty:

45% (medium)

Question Stats:

65% (01:56) correct 35% (01:59) wrong based on 213 sessions

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Electrical engineers have developed an energy-efficient type of light bulb that can replace the traditional incandescent bulb. The new bulb, known as the electronic lamp, operates by using a high frequency radio signal rather than the filament featured in incandescent bulbs. Although the electronic lamp currently costs 20 times as much as its traditional counterpart, its use will prove more cost effective in the long run. While a 100-watt incandescent bulb lasts 6 months if burned for 4 hours daily, a 25-watt electronic lamp used for the same amount of time each day lasts up to 14 years.

The argument above assumes that

A. the typical household use of a light bulb is approximately 4 hours a day

B. aside from its greater efficiency, the electronic lamp resembles the incandescent light bulb in most aspects

C. the type of light cast by the electronic lamp is different from that cast by an incandescent bulb

D. the price of electronic lamps will decrease as they are produced in increasingly greater quantities

E. a 100-watt incandescent light bulb does not provide significantly more light than a 25-watt electronic lamp

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Re: Electrical engineers have developed an energy-efficient type of light  [#permalink]

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05 Jan 2019, 06:59
IMO E

conclusion: its use will prove more cost effective in the long
prethink: there are NO certain factors that reduce the efficiency of the regular bulb to Electronic bulb

A. the typical household use of a light bulb is approximately 4 hours a day---incorrect, stated in passage

B. aside from its greater efficiency, the electronic lamp resembles the incandescent light bulb in most aspects---incorrect, conclusion is concerned about cost and efficiency

C. the type of light cast by the electronic lamp is different from that cast by an incandescent bulb---Incorrect, quality of light is not the concern

D. the price of electronic lamps will decrease as they are produced in increasingly greater quantities---Incorrect, no long term concern

E. a 100-watt incandescent light bulb does not provide significantly more light than a 25-watt electronic lamp ---Correct, if the input remains the same but the output decreases significantly than the efficiency decreases
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Re: Electrical engineers have developed an energy-efficient type of light  [#permalink]

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10 Jan 2019, 04:15
Bunuel wrote:
Electrical engineers have developed an energy-efficient type of light bulb that can replace the traditional incandescent bulb. The new bulb, known as the electronic lamp, operates by using a high frequency radio signal rather than the filament featured in incandescent bulbs. Although the electronic lamp currently costs 20 times as much as its traditional counterpart, its use will prove more cost effective in the long run. While a 100-watt incandescent bulb lasts 6 months if burned for 4 hours daily, a 25-watt electronic lamp used for the same amount of time each day lasts up to 14 years.

The argument above assumes that

A. the typical household use of a light bulb is approximately 4 hours a day

B. aside from its greater efficiency, the electronic lamp resembles the incandescent light bulb in most aspects

C. the type of light cast by the electronic lamp is different from that cast by an incandescent bulb

D. the price of electronic lamps will decrease as they are produced in increasingly greater quantities

E. a 100-watt incandescent light bulb does not provide significantly more light than a 25-watt electronic lamp

KAPLAN OFFICIAL EXPLANATION:

E

Here we need to identify an assumption. The author attempts to demonstrate that the "electronic lamp" can replace the incandescent bulb (that's the conclusion) because although the electronic lamp now costs much more, it will prove more cost effective in the long run (that's a summary of the evidence). He backs up this claim with numbers: A 25-watt electronic lamp can last 28 times longer than a 100-watt incandescent bulb while costing only 20 times as much as the bulb (thaT's the-hard evidence). There's one factor missing from the equation, though, and that's the amount of light the electronic lamp supplies. For the numbers given to support the author's conclusion, the electronic lamp and the normal bulb must each throw about the same amount of light. Otherwise, we might need 15 lamps for every bulb; and if this were the case, the argument would be dead wrong. Unless we assume, as (E) says, that the light produced by the lamp and the bulb is approximately equal, the evidence is meaningless.

(A) isn't assumed because the figure 4 hours a day doesn't have to represent typical household use; it need only provide a standard by which the lights can be compared. (B) is contradicted by the author. Since the electronic lamp operates by radio waves instead of a filament, it's clear that there are important structural aspects in which it differs from incandescent bulbs. (C) would actually make us doubt the reasonableness of the author's conclusion, so clearly it isn't assumed. If the electronic lamp is supposed to be a replacement for the incandescent bulb, its light should be similar to that produced by the bulb. (D) misconstrues why the electronic lamp is claimed to be cost effective in the long run-the point is that it lasts longer, not that it will become cheaper. The author is arguing that current electronic lamps are more cost effective, not that future lamps will be.
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Re: Electrical engineers have developed an energy-efficient type of light   [#permalink] 10 Jan 2019, 04:15
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