Definitions I often forget

Question 1

Keplers first law

Answer 1

The orbit of a planet is an ellipse, with the Sun at one of the two foci

Question 2

Keplers second law

Answer 2

A line segment joining the Sun to a planet sweeps out equal areas in equal time intervals

Question 3

Keplers third law

Answer 3

The square of the orbital time period T is directly proportional to the cube of the orbital radius r

Question 4

Explain emmision spectra

Answer 4

When an electron transitions from a higher energy level to a lower energy level, this results in the emission of a photon
Each transition corresponds to a different wavelength of light and this corresponds to a line in the spectrum
Each emitted photon has a wavelength which is associated with a discrete change in energy

Question 5

Explain absorbtion spectra

Answer 5

An atom can be raised to an excited state by the absorption of a photon
When white light passes through a cool, low pressure gas it is found that light of certain wavelengths are missing
When these electrons return to lower levels, the photons are emitted in all directions, rather than in the original direction of the white light

Question 6

Continuous spectra

Answer 6

Photons emitted from the core of a star contain all the wavelengths and frequencies of the electromagnetic spectrum
Continuous spectra are produced from hot, dense sources, such as the cores of stars