Question

The summer solstice in the southern hemisphere occurs on or about

Group of answer choices

June 21

March 21

September 21

July 4

December 21

n the H-R diagram, the vertical and horizontal axes are respectively

Group of answer choices

luminosity and temperature

luminosity and mass

color and brightness

spectral type and apparent magnitude

An asteroid is located between Mars and Jupiter. The semi-major axis of the asteroid’s orbit around the Sun is 3 AU. The period of the asteroid’s orbit is about ___________ years.

Group of answer choices

5.8

One of the most difficult problems for ancient astronomers to explain was the  

Group of answer choices

retrograde motion of the planets

eclipses of the Sun

annual motion of the Sun

phases of the Moon

cause of the seasons

One of the most difficult problems for ancient astronomers to explain was the  

Group of answer choices

retrograde motion of the planets

eclipses of the Sun

annual motion of the Sun

phases of the Moon

cause of the seasons

Which of the following is the first discovered Black Hole?

Group of answer choices

NGC 1921

Cygnus X-1

M 31

LGM

The force which was the first to split off from the “mother” force after the Big Bang is

Group of answer choices

the Weak Nuclear force

the EM force

the Strong Nuclear force

the force of Gravity

The period of time when the universe experienced a rapid inflation was when?

Group of answer choices

1-3 seconds

10^-35 --> 10^-32 sec

1-3 minutes

10^-43 --> 10^-35 sec

A large galaxy contains mostly old (Pop 2) stars spread smoothly throughout its volume, but it has little dust or gas. What type of galaxy is it most likely to be?

Group of answer choices

Elliptical

Spiral

Irregular

Barred Spiral

7.8

5.2

12.6

3.3

Which of the following statements about the Earth is incorrect?

Group of answer choices

its crust is divided into huge plates that jostle each other in a phenomenon called plate tectonics

it has an iron core

it has an average density of 4 gram per centimeter cubed

its atmosphere consists primarily of nitrogen and oxygen

Answer 1

1. The summer solstice in the southern hemisphere occurs around December 21.

2. In the Hertzsprung-Russel diagram or H-R diagram, the vertical and horizontal axes show respectively the luminosity and temperature.

3. According to Kepler’s third law:

  P²=a³ ; where p is the period of revolution in years and a is the semi-major axis in A.U.

Substituting the values, we have: -

P² = 3³

Or p = 3^3/2

Or p=5.196 years.

4. One of the most difficult problems of the ancient astronomers to explain was the retrograde motion of the planets.

5. The first Black hole to be discovered was Cygnus X-1 in 1971.

6. The force which was the first to split off from the “mother” force after the Big Bang is the force of Gravity.

7. The period of time when the universe experienced a rapid inflation was during 10^-35 – 10^-32 seconds.

8. The galaxy is most likely to be an elliptical one.

9. The Earth has an average density of about 5.51gm/cm³. Therefore the third option is incorrect.

Hope this helps. Thank You.