Small experimental vacuum tubes can operate in heat that makes semicon

Question

Small experimental vacuum tubes can operate in heat that makes semiconductor components fail. Any component whose resistance to heat is greater than that of semiconductors would be preferable for use in digital circuits, but only if that component were also comparable to semiconductors in all other significant respects, such as maximum current capacity. However, vacuum tubes’ maximum current capacity is presently not comparable to that of semiconductors.

If the statements above are true, which one of the following must also be true?

(A) Vacuum tubes are not now preferable to semiconductors for use in digital circuits.
(B) Once vacuum tubes and semiconductors have comparable maximum current capacity, vacuum tubes will be used in some digital circuits.
(C) The only reason that vacuum tubes are not now used in digital circuits is that vacuum tubes’ maximum current capacity is too low.
(D) Semiconductors will always be preferable to vacuum tubes for use in many applications other than digital circuits.
(E) Resistance to heat is the only advantage that vacuum tubes have over semiconductors.

tarunanandani · Answer

IMO A . It is the combination of the last two sentences of the passage.
 B is incorrect  because the passage doesn't talk about usage, it only mentions preference of vacuum tubes over semiconductors.
 C and E are extreme choices , 'only reason' 'only advantage'. These extreme statements are not supported by the passage.
 Choice D  talks about applications other than digital circuits and hence  is out of scope .

KarishmaB · Answer

Vacuum tubes can resist more heat than semiconductor components. 
A component whose resistance to heat is more will be preferable but only if it is comparable in other respects too such as maximum current capacity.
Vacuum tubes current capacity is not comparable yet.

Which of the following is a conclusion?

(A) Vacuum tubes are not now preferable to semiconductors for use in digital circuits.

Vacuum tubes are not comparable in other respects. It is not comparable in maximum current capacity. Hence they are not preferable to semiconductors. This is correct.

(B) Once vacuum tubes and semiconductors have comparable maximum current capacity, vacuum tubes will be used in some digital circuits.

We don't know that. Maximum current capacity is just one of the "other respects". Is it comparable in other "other respects" too? We don't know.

(C) The only reason that vacuum tubes are not now used in digital circuits is that vacuum tubes’ maximum current capacity is too low.

Again, is this the ONLY reason? Is it comparable in "other respects"? This may not be the "only reason".

(D) Semiconductors will always be preferable to vacuum tubes for use in many applications other than digital circuits.

Not known what will happen in the future.

(E) Resistance to heat is the only advantage that vacuum tubes have over semiconductors.

Not known from the argument.

Answer (A)

manishcmu · Answer

Here, we have a necessary condition -   only if  that component were also comparable to semiconductors in all other significant respects, such as maximum current capacity  which means if the component is not comparable to semiconductors in  any  of the other significant respects, then the component will not be preferable for use in digital circuits.
A - since vacuum tube is not comparable to semiconductors in one respect(maximum current capacity) => it will not be preferable for use in digital circuits
B- It says that if we fix maximum current capacity then we will be good. What about other features? What if conductivity of vacuum tube is lower than that of semiconductor? If this is true then it will not be preferable for use in digital circuits.

yc168 · Answer

OE for reference:

Overview:  
The passage compares vacuum tubes to semiconductors, with reference to their use in digital circuits. It tells us that certain experimental vacuum tubes have higher heat resistance than semiconductors, but, as things now stand, vacuum tubes' maximum current capacity is not comparable to that of semiconductors. The passage also gives us a standard for judging whether components with high heat tolerance (such as the experimental vacuum tubes) are preferable to semiconductors: any component with higher heat resistance than semiconductors is preferable for use in digital circuits if it is also comparable to semiconductors in all other significant respects, including maximum current capacity.

You are asked to find a statement that must be true if all the statements in the passage are true.

The Correct Answer:

A  According to the standard presented in the passage, for a component with high heat tolerance to be preferable to semiconductors for use in digital circuits, it must be comparable to semiconductors in all other significant respects, including maximum current capacity. But vacuum tubes are not presently comparable to semiconductors in maximum current capacity. Given this, it must be true that vacuum tubes are not now preferable to semiconductors for use in digital circuits.

The Incorrect Answer Choices:

B  (B) implies that vacuum tubes will one day have maximum current capacity comparable to that of semiconductors, but nothing in the passage suggests that this will ever be true. So this is one way in which (B) is not guaranteed to be true if the statements in the passage are true.

We can also rule out (B) by recalling that the passage indicates that vacuum tubes would be preferable for use in digital circuits if they were comparable to semiconductors in  all  other significant respects. Even if vacuum tubes are one day comparable to semiconductors in maximum current capacity, they still might not be comparable in other significant respects, which makes it possible that vacuum tubes would not be used in any digital circuits.

C  The passage says that vacuum tubes' maximum current capacity is not comparable to that of semiconductors. But it leaves open the possibility that vacuum tubes are not comparable to semiconductors in other significant respects. So the fact that vacuum tubes' maximum current capacity is too low might not be the only reason that they are not now used in digital circuits.

D  The passage does not say anything about the relative advantages and disadvantages of semiconductors as compared to vacuum tubes for applications other than digital circuits. So we cannot infer that semiconductors will always be preferable to vacuum tubes for many applications other than digital circuits. We cannot even infer that they are preferable.

E  The passage says that certain experimental vacuum tubes are more resistant to heat than semiconductors are. But it leaves open the possibility that vacuum tubes have other advantages over semiconductors.

Small experimental vacuum tubes can operate in heat that makes semicon

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Small experimental vacuum tubes can operate in heat that makes semicon

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