universe & solar system section 8 MCQ Questions & Answers Detailed Explanation

Answer: (c)

According to Nova hypothesis, Solar planets were formed because of explosion of Super Nova. A star becomes Super Nova in that stage when it has lacks hydrogen elements. A supernova happens where there is a change in the core, or center, of a star. A change can occur in two different ways, with both resulting in a supernova.

The first type of supernova happens in binary star systems. Binary stars are two stars that orbit the same point. One of the stars, a carbon-oxygen white dwarf, steals matter from its companion star. Eventually, the white dwarf accumulates too much matter. Having too much matter causes the star to explode, resulting in a supernova. The second type of supernova occurs at the end of a single star’s lifetime. As the star runs out of nuclear fuel, some of its mass flows into its core.

Eventually, the core is so heavy that it cannot withstand its own gravitational force. The core collapses, which results in the giant explosion of a supernova. The sun is a single star, but it does not have enough mass to become a supernova.

Answer: (a)

Earth’s early atmosphere contained only small amounts of free oxygen, probably produced entirely by the reaction of sunlight with water vapor from volcanoes. The oxygen-rich atmosphere that evolved later, and upon which oxygen-breathing life now depends, was a result of the origin of photosynthesis.

During the Precambrian, vast numbers of single-celled algae and cyanobacteria living in the seas eventually released enough oxygen to transform the environment.

Answer: (b)

Pluto was discovered by Clyde Tombaugh in 1930. According to International Astronomical Union (IAU) on August 24, 2006, Pluto is considered a dwarf planet. According to the definition, there are currently eight planets and five dwarf planets known in the solar system.

The five dwarf planets are Pluto, Ceres, Eris, Make make and Haumea. Pluto has been given number 134340.

Answer: (d)

Answer: (a)

Answer: (c)