Question

1.Elliptical galaxies tend to be redder in colour than spiral galaxies. Why is this?

Question 10 options:

A.The dust in spiral galaxies preferentially reflects blue light making the galaxy look bluer

B.Elliptical galaxies have more dust which reddens the light from them.

C.Elliptical galaxies have no star formation and are made of cooler, older stars.

D.Elliptical galaxies are farther away so their light is red shifted more

2. Dark energy is responsible for what aspect of the universe?

A.The accelerated rate of the expansion of the universe

B.Galaxy collisions

C.Galaxy formation

D.The creation of large scale structures in the universe

3.A star is observed to be orbiting a compact unseen companion. The unseen companion's mass is measured to be between 1.5 and 3 solar masses. What type of object is the companion likely to be?

A.Brown dwarf

B.Black hole

C.White dwarf star

D.Neutron star

Answer 1

1) Answer: (C) Elliptical galaxies have no star formation and are made of cooler, older stars.

Explanation: Elliptical galaxies have very little dust and hence there is very little star formation going on. They contain cooler and older stars. Therefore they appear redder.

2) Answer: (A) The accelerated rate of the expansion of the universe

Explanation: Dark energy creates a repulsive gravitational force and is coniderd to be the cause of accelerated rate of expansion of the universe

3) Answer: (D) Neutron star

Explanation: If the mass of star is more than 1.44 solar masses but less than 8 solar masess, it dies into a neutron star.