UPSC Prelims 2017 GS Paper I · Q87 of 100 General Science easy

What is the purpose of 'evolved Laser Interferometer Space Antenna (eLISA)' project ?

  1. (a) To detect neutrinos
  2. (b) To detect gravitational waves ✓ UPSC's answer
  3. (c) To detect the effectiveness of missile defence system
  4. (d) To study the effect of solar flares on our communication systems

Why the answer is (b)

• eLISA (evolved Laser Interferometer Space Antenna), now LISA, is the European Space Agency's planned space observatory of three spacecraft in a triangle with million-kilometre laser arms to detect low-frequency gravitational waves from merging supermassive black holes — option (b).

• LISA Pathfinder (2015–17) tested its technology; launch is planned for the 2030s.

• Neutrinos (a) are detected by facilities like IceCube; missile defence (c) and solar flares (d) are unrelated.

• Hence option (b).

Why the other options are wrong

(a) To detect neutrinos
Neutrino detectors are different instruments.
(c) To detect the effectiveness of missile defence system
eLISA has nothing to do with missile defence.
(d) To study the effect of solar flares on our communication systems
eLISA does not study solar flares.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2017, held on 18 June 2017. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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