Properties of the Sun - Class IX

Sun is very important to us as it is the main source of light and heat, i.e, the main source of energy. Besides, its gravitational force keeps all planets and other heavenly bodies in place.

Percentage of total number of atoms:
Hydrogen: $91.2$
Helium: $8.7$
Oxygen: $0.078$
Nitrogen: $0.0088$

Sun falls in the classification of stars. 

Sun is much closer to us as compared to other stars. Hence, it subtends larger angle at eyes compared to other stars and appear larger. Note that many stars are much larger than sun in size.

Sun is about 4.5 billion years old. 

Nuclear fusion means merging of separate elements as a unified whole to form heavy nuclei resulting in release of enormous amount of energy.

The sun is a star.

The angluar size of the Sun is 30 arcmin, 

The deepest layer of the Sun is the photosphere. This layer is the thinnest layer comprising of just 500 km in thickness.

Central region of the Sun is called the core. Core is where the nuclear reaction takes place. 

The diameter of the Sun is 1.3914 million km, it is 109 times larger than the diameter of the Earth and 10 times larger than Jupiter.

Spots formed on the surface of the Sun that are darker and cooler are called the Sun's spots.

This statement is false the Sun generates its own light due to Nuclear Fission not due to its large mass.

Sun is a large mass of gases. Two prominent gases forming the Sun are hydrogen and helium. Other gases such as carbon, nitrogen forms the trace amount.

The diameter of the Sun is 1.3914 million km.

The dark areas on sun produced by most intense magnetic helds are called sun spots.

The sun is a big ball of gas and plasma. Most of the gas 91 percent is hydrogen. It is converted into energy in the sun's core. The energy moves outward through the interior layers, into the sun's atmosphere, and is released into the solar system as heat and light.

Sunspots are temporary phenomena on the suns photosphere that appear as spots darker than the surrounding areas.

Ans: Sun spots 

The light from the sun to reach the surface of the earth takes about 8 min 20 sec.

Pearly white crown surrounding the sun visible during the total eclipse of sun is corona.

Sun spots form at mid latitudes and move towards equator.

Number of sun spots increase and decrease in a span of 11 years.

Sun's magnetic north and south pole get reversed in a cycle of 11 years. 

Solar flares are sudden, intense eruptions of radiation from the sun's surface, caused by the rapid release of magnetic energy that has built up in the solar atmosphere.

Ans: inhibition by strong magnetic field to the convective motion of the energy

Heliosphere is a bubble in space produced by the solar wind.

Irregular patches in the image of sun are sunspots.

Solar flares are associated with intense magnetic field. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released.

Radiative zone lies between the core and the convective zone. In radiative zone, energy resulted from the nuclear fusion in the core travels upwards by photons.

Sunspots are temporary phenomenon on the sun photosphere that appears as spots darker than the surrounding area.

Reason for enormous energy output of sun is the fusion reaction