Prelims 2023

Q36. Consider the following pairs:
Object in space – Description

1. Cepheids – Giant clouds of dust and gas in space
2. Nebulae – Stars which brighten and dim periodically
3. Pulsars – Neutron stars that, are formed when massive stars run out of fuel and collapse

How many of the above pairs are correctly matched?
a. Only one
b. Only two
c. All three
d. None

Question from UPSC Prelims 2023 GS Paper

Explanation : 

Correct Answer – a. Only One

Cepheids – Stars Which Brighten and Dim Periodically

  • Cepheids are a type of variable star that exhibit a regular pattern of brightening and dimming. They are used as distance indicators in astronomy because their period of variation is directly related to their luminosity.

Nebulae – Giant Clouds of Dust and Gas in Space

  • Nebulae are indeed giant clouds of dust and gas in space. They are the birthplaces of stars, as the dust and gas within them come together under the force of gravity to form new stars.

Pulsars – Neutron Stars That Are Formed When Massive Stars Run Out of Fuel and Collapse

  • Pulsars are a type of neutron star that emit beams of electromagnetic radiation out of their magnetic poles. As the star rotates, these beams sweep across the sky, creating a pulsing effect when observed from Earth. They are formed when massive stars run out of fuel and collapse, so this pair is correctly matched.
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