Space

Question 1

Evidence for big bang

Answer 1

Red shift - galaxies are moving away from us. This can either mean that we are at the centre of the universe, which disproves the cosmological principle SO it must mean that the universe is expanding at every point. More distant galaxies are more red shifted so are receding at a faster rate.
Cosmic background radiation- when the universe was first made it was very small, hot and dense. There was lots of gamma radiation and as it expanded the gamma radiation stretched out into microwaves. As it expanded the universe also cooled down drastically.

Question 2

Keplers 1st Law

Answer 2

• The orbit of a planet is an ellipse with the sun at one focus

Question 3

Keplers 2nd Law

Answer 3

• A line segment joining a planet and the sun sweeps out equal areas during intervals of equal time.

Question 4

Keplers 3rd Law

Answer 4

Period^2 is directly proportional Radius^3

Question 5

Cosmological Priniciple

Answer 5

The universe is isotropic and homogenous and the laws of physics apply everywhere in it.

Question 6

Equation relating distance & parallax angle

Answer 6

d = 1/p
distance is in parsecs. only works for stars at max 100pc away.

Question 7

Recessional velocity equation

Answer 7

recessional velocity = hubbles constant x distance

Question 8

Hubbles constant

Answer 8

67.8 kms-1Mpc-1 but to find age of the universe have to use 2.2x10^-18 s-1
1/Hubbles constant = age of universe.

Question 9

Emission line spectra

Answer 9

Every element has a unique one because of the unique set of energy levels associated with its electrons. It looks like coloured lines on a black background.

Question 10

Continuous line spectra

Answer 10

All visible wavelengths of light are present, this is produced by a solid heated metal.

Question 11

Absorption line spectra

Answer 11

Looks like black lines against a colourful (continuous spectra) background. Each black line corresponds to a wavelength of light used to excite atoms of that element. These wavelengths are the same for when those atoms are de-excited.

Question 12

Isotropic

Answer 12

looks the same in every direction

Question 13

Assumptions of kinetic theory of gases

Answer 13

• Forces are negligible except during collisions
• Collisions are perfectly elastic
• Particles occupy negligible volume compared to volume of gas
• Lots of particles move in random motion

Question 14

Two conditions of SMH

Answer 14

acceleration is proportional to displacement
and acts in the opposite direction.

Question 15

How to find Vmax in SMH

Answer 15

v max= w * A
which then can be used to find max KE (also equal to total energy

Question 16

Height difference for pendulum

Answer 16

If height difference of pendulum is given this is not amplitude. Use mgh=1/2mv^2 to find max velocity then can use Vmax= w*A

Question 17

Luminosity

Answer 17

Total radiant power given out by a star

Question 18

Arcsecond

Answer 18

is equal to 1degree / 60 / 60