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

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: (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: (b)

The approximate diameter of Earth is 12800 km. The rotation of the planet has slightly flattened it out, so it has a larger diameter at the equator than at the poles.

The equatorial diameter of Earth is 12,756 km, its polar diameter is 12,713 km, and its average diameter, which is referred to in common usage, is 12,742 km or 7,926 miles.

Answer: (b)

Answer: (b)

Jupiter was named after the Roman God Zeus. Zeus is the “Father of Gods and men” who rules the Olympians of Mount Olympus as a father rules the family according to the ancient Greek religion.

He is the God of sky and thunder in Greek mythology. Zeus is etymologically cognate with and, under the Hellenic influence, became particularly closely identified with Roman Jupiter.

Answer: (b)

The corona is the outermost layer of the Sun, starting at about 1300 miles (2100 km) above the solar surface (the photosphere).

The temperature in the corona is 500,000 K (900,000 degrees F, 500,000 degrees C) or more, up to a few million K. The corona cannot be seen with the naked eye except during a total solar eclipse.

The corona does not have an upper limit.