universe & solar system section 10 MCQ Questions & Answers Detailed Explanation

Answer: (a)

Continental Drift and Palaeomagretism forms Plate Tectonic Theory.

Plate tectonics is the theory that the outer rigid layer of the earth (the lithosphere) is divided into a couple of dozen “plates” that move around across the earth’s surface relative to each other, like slabs of ice on a lake.

Answer: (c)

A solar eclipse occurs when the moon crosses the path between the sun and the earth. The darkest shadow (where the sun is completely covered) is called the umbra.

The umbra is narrow at the distance of the Earth, and a total eclipse is observable only within the narrow strip of land or sea over which the umbra passes. The partial shadow is called the penumbra.

Answer: (d)

Venus is smaller in size than the Earth. Diameter of earth is12,742 km while that of Venus is 12,100 km

Answer: (d)

• Planet Earth has been called the “Blue Planet” due to the abundant water on its surface.
• Pluto, once considered the ninth and most distant planet from the sun, is now the largest known dwarf planet in the solar system. It is also one of the largest known members of the Kuiper Belt, a shadowy disk-like zone beyond the orbit of Neptune thought to be populated by hundreds of thousands of rocky, icy bodies each larger than 62 miles (100 kilometres) across, along with 1 trillion or more comets.
• Moon is the natural satellite of Earth.
• The sun is considered a star because it has all the characteristics of one.

Answer: (a)

Answer: (d)

The tail of the comet is always away from the Sun because the comet rotates around the Sun, the lighter mass of the comet is pushed away due to the centrifugal force alone. The tail of a comet is made up of gas and tiny particles that are carried away from the sun by the solar wind.

Comets are formed mostly from ice and dust, and their tails only form when they are close enough to be melted by the heat from the sun. As the nucleus of a comet begins to melt, it forms a cloud of gas and small particles known as the coma.

When comets travel close enough into the center of our solar system, pressure from sunlight causes the coma to form a tail that stretches away from the sun.