universe & solar system section 8 MCQ Questions & Answers Detailed Explanation

Question : 1

Study the following statements and select the correct answer from the codes given below:

1. The average density of rocks in the lower crust of the earth is 3.
2. There is a gradual decrease in the velocity of the seismic waves through the lower crust.
3. The mantle-core boundary is marked by Moho-discontinuity.
4. The outer core of the earth is in molten form.

a) 3 and 4 are correct

b) 1 and 4 are correct

c) 2 and 3 are correct

d) 1 and 2 are correct

Question : 2

When there is noon at I.S.T. meridian people another place of the Earth are taking their 6 O’ clock morning tea. The longitude of the place is

a) 172°30’ E

b) 90° W

c) 7°30’ W .

d) 17°30’ E

Question : 3

The causes of Day and Night is

a) Tilt of Earth’s axis

b) Moon’s rotation

c) Rotation of Earth on its axis

d) Earth-rotation

Question : 4

The planet emitting green light is

a) Uranus

b) Neptune

c) Venus

d) Jupiter

Question : 5

On which date is the earth in perihelion ?

a) January 3

b) July 4

c) Dec 22

d) June 21

Question : 6

‘Super nova’ is

a) an exploding Star

b) a black hole

c) an asteroid

d) a comet