Q15 of 25 Page 101

A star is ten light years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change?

Light year is the unit of measurement of distance. 1 light year is equal to the distance travelled by light in one year. So if a star is located ten light years away from the Earth which brightens up today then it will be visible to our eyes after ten years.


More from this chapter

All 25 →
13

In the given Fig. 17.4 out of the positions A,B,C and D which will indicate the position of the sun? Draw the sun at the appropriate position.


 14

In Fig. 17.5 mark the arrows (←), (→), (↓), or (↑) to show the direction of sunlight.


 16

Meteors are not visible during the daytime. Explain the reason.

 17

Why does the moon change its shape daily?