CIE A Level Physics复习笔记25.2.2 Doppler Redshift
Redshift of EM Radiation 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 ob...
CIE A Level Physics复习笔记25.2.1 Emission Spectra
Emission Spectra Astronomers are very limited in how they can investigate objects in the space All of the techniques used involve analysing the light emitted from the star, or galaxy One of these t...
CIE A Level Physics复习笔记25.1.4 Stefan-Boltzmann Law & Stellar Radii
Stefan-Boltzmann Law A star’s luminosity depends on two factors: Its surface temperature Its radius The relationship between these is known as the Stefan-Boltzmann Law, which states: The total ener...
CIE A Level Physics复习笔记25.1.3 Wien's Displacement Law
Wien's Displacement Law Wien’s displacement law relates the observed wavelength of light from a star to its surface temperature, it states: The black body radiation curve for different temperatures...
CIE A Level Physics复习笔记25.1.2 Standard Candles & Stellar Distances
Standard Candles A standard candle is defined as: An astronomical object which has a known luminosity due to a characteristic quality possessed by that class of object Examples of standard candles ...
CIE A Level Physics复习笔记25.1.1 Luminosity & Radiant Flux
Defining Luminosity Luminosity L is defined as: The total power output of radiation emitted by a star It is measured in units of Watts (W) Radiant flux intensity F is defined as: The observed amoun...
CIE A Level Physics复习笔记24.2.3 Detecting Gamma-Rays from PET Scanning
Detecting Gamma-Rays from PET Scanning The patient lays stationary in a tube surrounded by a ring of detectors Images of slices of the body can be taken to show the position of the radioactive trac...
艺术留学热门专业推荐
近年来，随着设计、艺术行业的发展，人们的审美和艺术需求日益增加，艺术设计领域已经摆脱了小众的标签，越来越多人进入这个专业领域，除了对艺术始终保持兴趣的艺术生，很多在综合类学校的非艺术生也中途选择了...
CIE A Level Physics复习笔记24.2.2 Annihilation in PET Scanning
The Process of Annihilation When a positron is emitted from a tracer in the body, it travels less than a millimetre before it collides with an electron The positron and the electron will annihilate...
CIE A Level Physics复习笔记24.2.1 Radioactive Tracers
Radioactive Tracers A radioactive tracer is defined as: A radioactive substance that can be absorbed by tissue in order to study the structure and function of organs in the body Radioactive isotope...
CIE A Level Physics复习笔记24.1.8 Computed Tomography Scanning
Computed Tomography Scanning A simple X-ray image can provide useful, but limited, information about internal structures in a 2D image When a more comprehensive image is needed, a computerised axia...
CIE A Level Physics复习笔记24.1.7 Attenuation of X-rays in Matter
Attenuation of X-rays in Matter Bones absorb X-ray radiation This is why they appear white on the X-ray photograph When the collimated beam of X-rays passes through the patient’s body, they are abs...
