2 slides filled with information about P1B - a Physics GCSE topic in England. P1B is Radiation & The Universe so everything you need to know for your GCSE exam is on this presentation.Read less
![All EM waves travel through space at speed of light (300 million m/s). Wave speed= Frequency X Wavelength (m/s) (Hz) (m) X-rays and gamma rays are absorbed by dense material such as bone and metal but pass through soft tissue X-rays and gamma rays damage living tissue when they pass through it. Large doses can kill cells, small doses can cause cancer ,[object Object],[object Object],[object Object],Ultraviolet-UV Found naturally in sunlight. UV harms the skin and eyes, causes a sun tan, used in security markers Radio waves are reflected by the IONOSPHERE. Stronger in summer Analogue signals vary continuously in amplitude or frequency Digital signals are on or off. Digital signal free of interference and carry more information. Carrier waves (radio, microwaves etc) carries digital/analogue signal ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],X-rays are used in hospitals to take radiographs. The use of radio waves depends on the frequency of the waves P1b, Physics](https://image.slidesharecdn.com/p1brevision-101210125311-phpapp01/85/P1B-Revision-Template-English-Physics-Unit-1B-Revision-Guide-1-320.jpg)
![Marie Curie- Discovered Radioactivity. Worked with uranium. Died of cancer because of her work. Unstable radioactive elements decay randomly and give off particles Isotope atoms of an element have different numbers of neutrons Detect radiation with Geiger Muller Tube (GM tube) Alpha Radiation- Stopped by paper or a few cm of air Beta Radiation – Stopped by thin aluminium or about 1m of air Gamma radiation- Stopped by thick lead or concrete and has an unlimited range in air Alpha particle Positive charge, deflected in magnetic and electric fields, Helium nucleus Beta particle Negative charge, deflected in magnetic and electric fields, electron emitted from nucleus Gamma particles No charge, not deflected in magnetic and electric fields, EM wave Ionisation- Alpha and beta particles knock electrons out of atoms ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],The Earths atmosphere absorbs all electromagnetic waves, except visible light , radio waves and some UV radiation. Satellite detectors are used to make observations outside the visible and radio spectrum. Clear images are observed using telescopes on satellites detecting visible light. Half life Time it takes for number of radioactive nuclei of the isotope to decay to half its initial value. P1b Physics A radioactive substance contains unstable nuclei. An unstable nucleus becomes stable by emitting radiation. The most distant galaxies are about 13 million light years away. ,[object Object],[object Object],Isotopes Different types of atoms of the same chemical element, each having a different number of neutrons](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)