Atomic Mass Unit The unified atomic mass unit (u or sometimes a.m.u) is roughly equal to the mass of one proton or neutron: 1 u = 1.66 × 10−27 kg This value is provided on the exam data sheet The a...
Nuclear Binding Energy Experiments into nuclear structure have found that the total mass of a nucleus is less than the sum of the masses of its constituent nucleons This difference in mass is known...
The Hubble Constant By rearranging the equation for Hubble’s law, we can determine that the Hubble constant, H0, is: Where: v = recessional velocity of an object (km s–1) d = distance between the o...
Redshift Equation Recall the Doppler effect is defined as: The apparent change in wavelength or frequency of the radiation from a source due to its relative motion away from or toward the observer ...
Doppler Shift If a wave source is stationary, the wavefronts spread out symmetrically If the wave source is moving, the waves can become squashed together or stretched out If the wave source is mov...
The Life Cycle of Stars The life cycle of stars go in predictable stages The exact route a star's development takes depends on its initial mass Initial Stages for All Masses The first four stages i...
近些年，越来越多的家长意识到国际教育的重要性，A-level课程也成为众多家长和学生的首选。今天就为大家盘点一下，Alevel课程A*高分及最难的科目，为进入世界顶级学府做准备。 Alevel的A*标准 Alevel的每一科考试...
The Hertzsprung - Russell Diagram Danish astronomer Ejnar Hertzsprung, and American astronomer Henry Noris Russell, independently plotted the luminosity of different stars against their temperature...
Determining distance using standard candles Standard Candles A standard candle is defined as: An astronomical object which has a known luminosity due to a characteristic quality possessed by that c...
