LIGO stands for
- A.Laser Interferometer Gravitational wave Observatory
- B.Light Interferometer Gravitational wave Observatory
- C.Light Induced Gravity Observatory
- D.Laser Induced Gaseous Optics
Correct answer
Explanation
The correct answer is A, Laser Interferometer Gravitational wave Observatory. LIGO uses laser beams in long perpendicular arms to detect the tiny stretching of space caused by gravitational waves.
LIGO has two detectors in the United States, at Hanford in Washington and Livingston in Louisiana, each with arms 4 km long. In September 2015 they recorded the first direct gravitational waves, from two black holes merging over a billion light years away, confirming a prediction of Einstein's general theory of relativity. Rainer Weiss, Kip Thorne and Barry Barish received the 2017 Nobel Prize in Physics for this work. A third detector, LIGO-India, is being built at Aundha in Hingoli district of Maharashtra.
B is wrong because the instrument uses lasers, not ordinary light. C is wrong because LIGO measures gravitational waves with interferometry; nothing is light-induced. D is wrong because the observatory has nothing to do with gaseous optics.
Exam tip: LIGO detected gravitational waves in 2015; LIGO-India is coming up in Hingoli, Maharashtra.
Practice Questions
View allWho among the following built a model steam engine in 1698 called "Miner's Friend" to drain mines ?
- A.Thomas Savery
- B.Thomas Newcomen
- C.James Watt
- D.Richard Arkwright
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The English engineer Thomas Savery patented a steam pump in 1698 and called it the Miner's Friend, as it was meant to pump water out of flooded mines.
Read the full explanation →A metallic wire having resistance of 20 Ω is cut into two equal parts in length. These parts are then connected in parallel. The resistance of this parallel combination is equal to
- A.20 Ω
- B.10 Ω
- C.5 Ω
- D.15 Ω
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Each half of the wire has a resistance of 10 Ω, and two 10 Ω resistors in parallel give 5 Ω. The resistance of a wire is R = ρL/A, so it is directly proportional to its length when the material and thickness stay the same.
Read the full explanation →Myopia is a defect in human vision where an image of a
- A.nearby object is focused beyond the retina.
- B.nearby object is focused before the retina.
- C.distant object is focused before the retina.
- D.distant object is focused beyond the retina.
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In myopia, or short-sightedness, a person sees near objects clearly but distant objects look blurred because their image forms in front of the retina.
Read the full explanation →A homogeneous mixture contains two liquids. How are they separated ?
- A.By filtration
- B.By evaporation
- C.By distillation
- D.By condensation
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Two miscible liquids that form a homogeneous mixture are separated by distillation, which uses the difference in their boiling points.
Read the full explanation →Cartilage is NOT found in
- A.larynx
- B.nose
- C.ear
- D.urinary bladder
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The urinary bladder is a hollow muscular sac made of smooth muscle and a stretchable lining; it has no cartilage.
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