P8.3.3-4

Question 1

Give an example of the components in our Solar System.

Answer 1

Sun
Planets - Mercury, Venus, Earth, Mars..
Minor planets - Pluto 
Natural satellites - moons
Artificial satellites - man made ones that usually orbit Earth

Question 2

What are the 2 types of orbit?

Answer 2

Geostationary, polar

Question 3

What are the features of geostationary orbits?

Answer 3

• High (36,000km above equator), orbit every 24hrs

- Remain in a fixed position above Earth’s equator

Question 4

Give some uses of a geostationary orbit.

Answer 4

Communications and satellite

- Stay in the same point so it’s easy to point transmitters and receivers at them.

Question 5

What are the features of polar orbits?

Answer 5

• Low (2,000km) every 2 hours (fast)

- Orbit over the poles

Question 6

Give some uses of polar orbits.

Answer 6

• Military (spying)
• Observation of Earth
• Weather

Question 7

Why are orbits circular?

Answer 7

Objects travelling in a circle are accelerating due to the change in direction, there has to be a force to cause acceleration, this is gravity. Normally the gravity would cause it to go to the Earth but since it is already moving, just the direction changes. (There is a precise speed for this, too fast it will fly off, too slow it will go to Earth’s centre)

Question 8

All objects emit radiation, what does the radiation intensity and distribution depend on?

Answer 8

The temperature

Question 9

What happens when an object is hot?

Answer 9

Radiation emitted is of a higher frequency and shorter wavelength.

Vice versa for colder (lower frequency and longer wavelength)

Question 10

Why do hot objects emit visible light?

Answer 10

They have short wavelengths of radiation emitted

Question 11

What does the temperature of an object depend on?

Answer 11

If an object emits more radiation than it absorbs, the temperature increases vice versa.

Stays constant if emitting and absorbing is the same