CIE A Level Physics復習筆記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...
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...
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...
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...
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 ...
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...
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...
近年來,隨著設計、藝術行業的發展,人們的審美和藝術需求日益增加,藝術設計領域已經擺脫了小眾的標簽,越來越多人進入這個專業領域,除了對藝術始終保持興趣的藝術生,很多在綜合類學校的非藝術生也中途選擇了...
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...
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...
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...
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...
Production of X-rays X-rays are short wavelength, high-frequency part of the electromagnetic spectrum They have wavelengths in the range 10?8?to 10?13?m X-rays are produced when fast-moving electro...
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