1) Home page for all Unit 5 lessons
https://youtu.be/HeOn6U2sxh4
2) Home page for all discussions on Unit 5 past papers
https://youtu.be/2HqIpgHlkcs
3) Calculation of unit error 6
https://youtu.be/UsPzXTdrILE
4) Home page for all Unit 4 lessons
https://youtu.be/OeUr7kEzgoY
5) Home page for all discussions on Unit 4 past papers
https://youtu.be/EC7zdpLq3nA

00:00 Cosmology or astrophysics revision lesson Edexcel IAL Unit 5 WPH15/01
0:10 Importance of cosmology
6:01 Black body and law by Stefan Boltzmann
9:02 Vienna law
4:18 p.m. Question on Stefan Boltzmann and Wien's law
18:24 Measuring the surface temperature of a star
10:14 p.m. Main sequence star and star classes
29:50 Star class ranking
31:16 Mass of a star and its lifetime in the main sequence
33:35 Stellar Evolution
35:20 Stellar evolution of a low mass star
51:32 Stellar evolution of a massive star
59:40 Diagram Hertzsprung Russel HR
1:03:26 Units in astronomical distances
1:03:59 Astronomical unit AU
1:04:51 Light year
1:06:53 Parallax second or parsec
1:11:48 Measuring the distance of a star or galaxy
1:12:53 Parallax trigonometry method
1:21:53 Parallax spectroscopic method
1:27:52 Standard candle
1:32:10 Cepheid variable as standard candle
1:40:40 Doppler effect and Hubble's law
1:52:30 Question on the Doppler effect and Hubble's law
1:55:31 Age of the universe – Estimate
2:01:55 Dark matter
2:08:25 Dark energy
2:10:08 Are dark energy and dark matter equivalent?
2:11:23 Cosmic microwave background radiation CMBR

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