universe & solar system section 9 MCQ Questions & Answers Detailed Explanation

Answer: (d)

Answer: (c)

Answer: (c)

The group of stars arranged in a definite pattern is called a constellation. In modern astronomy, a constellation is an internationally defined area of the celestial sphere.

These areas are grouped around asterisms, which are patterns formed by prominent stars within apparent proximity to one another on Earth’s night sky.

Answer: (d)

Latitude is distance North or south of the equator. It may also be defined as an angle which ranges from 0° at the equator to 90° at the poles.

Answer: (c)

The inexhaustible source of energy of the stars is due to the conversion of Hydrogen to Helium. In the interior of a star, the particles move rapidly in every direction because of the high temperatures present.

Every so often a proton moves close enough to a nucleus to be captured, and a nuclear reaction takes place. Only protons of extremely high energy (many times the average energy in a star such as the Sun) are capable of producing nuclear events of this kind. The minimum temperature required for fusion is roughly 10 million K.

Since the energies of protons are proportional to temperature, the rate of energy production rises steeply as temperature increases.

Answer: (c)