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Question 2

Name the largest planet of the solar system.

Jupiter (Brihaspati).


Question 3

What is a constellation? Name any two constellations.

constellations are a group of stars that appear to form some recognizable shape. For examples, Ursa Major and Orion.


Question 4

Draw sketches to show the relative positions of prominent starts in:
(a) Ursa Major and (b) Orion.


(a)Ursa Major


(b) Orion

Question 5

Name two objects other than planets which are members of the solar system.

A collection of a large number of smallobjects, gases and dust are revolving around the sun. They occupy a large gap between the orbits of Mars and Jupiter. However, these are not planets. These celestial objects are knowns as asteroids.
(ii) Meteors:-
Meteors are small celestial objects that are seen as bright streaks of light in the sky.
They brunt out on entering the Earths atmosphere because of the heat produced by friction. They results in bright streaks in the sky. They are not planets.

Question 6

Explain how you can locate the Pole Star with the help of Ursa Major.

Pole star can be located with the help of the two stars at the end of Ursa Major. Imagine a straight line passing through these stars as shown in Fig. 17.4 Extend this imaginary line towards the north direction. (About five times the distance between the two stars). This line will lead to a star which is not too bright. This is the Pole Star. Verify that the Pole star does not move as all other stars drift from east to west.


Question 7

Do all the stars in the sky move? Explain.


No stars actually do not move but they only appear to move from east to west, as the earth from where we see them, rotates from west to east. However pole star, which is situated in the direction of the earth’s axis. It does not appear to move.


Question 8

Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the earth?

The sun is nearly 150,000,000 kilometres (150 million km) away from the earth.

The next nearest star to the earth after the Sun is Alpha Centauri. It is at a distance of about 40,000,000,000 km from the earth. Some stars are even further away. It is not convenient to express such distances in kilometers.

Such large distance are expressed in another unit known as light year. One light year is the distance traveled by light in one year.

If we say that a star is eight light years away from earth, it means that the light from that star will reach the earth in eight years.


Question 9

The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accommodate?

Volume of the earth= 4/3 πR3

Volume of Jupiter =4/3
π (11)3

Ratio of volume of Earth and Jupiter is 1: 1331

The number of Earths Jupiter can hold = 113

= 11 x 11 x 11= 1331.

Question 10

Boojho made the following sketch of the solar system. Is the sketch correct? If not, correct it.


It is not correct . Draw the picture of solar system as given in Fig.


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