Consider the following pairs:
Objects 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
Answer: A
Let’s analyze each pair:
- Cepheids: Giant clouds of dust and gas in space.
- This pair is incorrect. Cepheids are not giant clouds of dust and gas in space. Cepheids are a type of variable star that brighten and dim periodically due to pulsations in their outer layers.
- Nebulae: Stars which brighten and dim periodically.
- This pair is incorrect. Nebulae are not stars that brighten and dim periodically. Nebulae are vast clouds of dust, hydrogen, helium, and other gases in space. They can be the birthplaces of stars, but they do not exhibit the periodic brightness variation.
- Pulsars: Neutron stars that are formed when massive stars run out of fuel and collapse.
- This pair is correct. Pulsars are highly magnetized, rotating neutron stars that emit beams of electromagnetic radiation. They are formed when massive stars undergo a supernova explosion, leaving behind a dense, rapidly rotating neutron star.
Therefore, out of the given pairs, only one (Pair 3 – Pulsars) is correctly matched. The correct answer is (a) Only one.
