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# Nuclear fusion is a process whereby the nuclei of atoms are

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Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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Updated on: 13 Dec 2017, 07:17
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Nuclear fusion is a process whereby the nuclei of atoms are joined, or “fused,” and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using “heavy” water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion ad been achieved.

Which one of the following, if true, would cast doubt on the experimenters’ conclusion?

(A) Helium-4 was not the only gas found in the experiment chamber.
(B) When fusion is achieved, it normally produces several by-products, including tritium and gamma rays.
(C) The amount of helium-4 found in the chamber’s air did not exceed the amount of Helium-4 that is found in ordinary air.
(D) Helium-4 gas rapidly breaks down, forming ordinary helium gas after a few hours.
(E) Nuclear fusion reactions are characterized by the release of large amounts of heat.

Source: LSAT

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Originally posted by broall on 23 Sep 2017, 03:03.
Last edited by Skywalker18 on 13 Dec 2017, 07:17, edited 1 time in total.
corrected spelling in OA option
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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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24 Sep 2017, 03:11
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I am winking on answer C as I am breathing ordinary air with plenty of helium 4....Anyone disagrees...
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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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24 Sep 2017, 05:54
agree ..C is the right answer as it cast a doubt that helium released was from nuclear reaction or not.
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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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24 Sep 2017, 07:26
This is pretty straight forward!

We have to cast a doubt on the conclusion of the experimenter that the
Helium-4 gas formed during the experiment is formed due to the experiment.
But, if we consider Option C(The amount of helium-4 found in the chamber’s air
did not exceed the amount of Helium-4 that is found in ordinary air)
, then the
conclusion is weakened
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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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13 Dec 2017, 07:21
Nuclear fusion is a process whereby the nuclei of atoms are joined, or “fused,” and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using “heavy” water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion ad been achieved.

Which one of the following, if true, would cast doubt on the experimenters’ conclusion?

(A) Helium-4 was not the only gas found in the experiment chamber.-- Irrelevant
(B) When fusion is achieved, it normally produces several by-products, including tritium and gamma rays. -- Irrelevant
(C) The amount of helium-4 found in the chamber’s air did not exceed the amount of Helium-4 that is found in ordinary air.--supplies an alternative cause. The helium-4 was found in the air in the chamber because helium-4 (in that quantity) is always found in air. There's no "special" amount of helium-4, so there's no reason to believe that fusion occurred (which would have resulted in some "extra" helium-4).
(D) Helium-4 gas rapidly breaks down, forming ordinary helium gas after a few hours. -- Irrelevant
(E) Nuclear fusion reactions are characterized by the release of large amounts of heat. -- Irrelevant

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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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15 Nov 2018, 01:50
Nuclear fusion is a process whereby the nuclei of atoms are joined, or “fused,” and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using “heavy” water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion ad been achieved.

Which one of the following, if true, would cast doubt on the experimenters’ conclusion?

(A) Helium-4 was not the only gas found in the experiment chamber.
(B) When fusion is achieved, it normally produces several by-products, including tritium and gamma rays.
(C) The amount of helium-4 found in the chamber’s air did not exceed the amount of Helium-4 that is found in ordinary air.
(D) Helium-4 gas rapidly breaks down, forming ordinary helium gas after a few hours.
(E) Nuclear fusion reactions are characterized by the release of large amounts of heat.

Although I chose the correct answer, I have a small doubt on Answer B. The conclusion that we have to weaken is that fusion had been achieved. So, in B, if the achievement of fusion produces several by-products, doesn't the fact that no several by-products has been created after fusion also cast doubt on the conclusion?

Thanks
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Re: Nuclear fusion is a process whereby the nuclei of atoms are  [#permalink]

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27 Feb 2019, 04:21
broall wrote:
Nuclear fusion is a process whereby the nuclei of atoms are joined, or “fused,” and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using “heavy” water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion ad been achieved.

Which one of the following, if true, would cast doubt on the experimenters’ conclusion?

(A) Helium-4 was not the only gas found in the experiment chamber.
(B) When fusion is achieved, it normally produces several by-products, including tritium and gamma rays.
(C) The amount of helium-4 found in the chamber’s air did not exceed the amount of Helium-4 that is found in ordinary air.
(D) Helium-4 gas rapidly breaks down, forming ordinary helium gas after a few hours.
(E) Nuclear fusion reactions are characterized by the release of large amounts of heat.

Source: LSAT

C is the correct answer. If the Helium 4 quantity is not different from the amount normally found in air, therefore it cannot be argue that fusion happened since it is as likely that the helium 4 is due to normal circumstance as it is as a byproduct of fusion.
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Re: Nuclear fusion is a process whereby the nuclei of atoms are   [#permalink] 27 Feb 2019, 04:21
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# Nuclear fusion is a process whereby the nuclei of atoms are

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