Question

Diameter of the Sun is _____.
A. 12 lakh km
B. 13 lakh km
C. 14 lakh km
D. 15 lakh km

Answer 1

Hint: Diameter is a straight line joining two points on the surface of a sphere and passes through the centre of the sphere. The star which is closest to the earth is called the Sun.

Complete answer:
A celestial body which emits heat and light from the plasma that it holds with its gravity is called ‘star’. The star which is closest to the earth is called the Sun. It is located at the centre of our solar system. It has a diameter of 14 lakh km which is almost 100 times the diameter of the earth. The total mass of the sun comprises 73% hydrogen, 25% helium and small quantities of heavier elements like carbon, oxygen, iron and neon. The sun is so huge that it accounts for 99% of the total mass of the entire solar system.

The main reason for the sun to emit heat and light is the nuclear fusion reactions that occur on its surface. Every second, tons of hydrogen atoms fuse together and form helium atoms. Some matter gets converted from hydrogen to helium and some of the matter itself gets converted into energy (heat and light).
It is the most important source of energy for our planet. It is 15,00,00,000km away from the earth. This distance is called an astronomical unit and used as the standard unit for measuring huge distances across the universe. It takes about 8 minutes for light to cover this distance. The sun allows plants to perform photosynthesis and it also controls the weather and climate of the earth.

Hence, the correct answer is option (C)

Note: The energy that comes from sunlight supports 99% of the life on earth, the remaining 1% being the aquatic plants and organisms at the bottom of the oceans which do not know about the existence of the sun and get their energy from the earth geothermal heat.