Exercise - Question:

Que: Draw sketches to show the relative positions of prominent stars in

(a) Ursa Major and

(b) Orion

Ans: 

(i) Ursa Major

(ii) Orion

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

Ans: Comets and asteroids.

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

Ans: Pole star can be located with the help of two stars at the end of Ursa Major. Imagine a straight line passing through these stars. Extend the imaginary line in North direction. This line is about five times the distance between two stars. A star is seen in this direction which is called Pole star.

Que: Do all the stars in the sky move? Explain.

Ans: No, all the stars do not move in the sky. Due to the rotation of the Earth on its own axis stars seem to move in the sky.

Que: 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?

Ans: The stars are very far away from the Earth and it is not convenient to express such distances in kilo¬metres. Thus, such large distances are expressed in unit known as light year.
If we say that a star is eight light years away from Earth, it means that the light from star will reach the Earth in eight years.

Que: 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 accomodate?

Ans: Let the radius of Earth be r units.

Que: Boojho made the following sketch (Fig. 17.6) of the solar system. Is the sketch correct or not, correct it.

Ans: No, the sketch made by Boojho is not correct. The correct sketch is given below: