High frequency + high energy,   ionising 

What are the characteristics of a short wavelength?

Low frequency + low energy, non-ionising 

What are the characteristics of a long wavelength? 

Visible light, infrared, microwaves,radio waves 

 visible light - Photography, infrared - remote control, microwaves - satellite comms, radio waves - radio/ tv signals

Name the application of low frequency EMs 

gamma - cancer treatment X-rays - medical treatment ultraviolet - CSI 

Name the applications of short frequency EMs 

crime scene , some chemicals absorbs uv light and emits visible light 

direct high energy gamma rays/x-rays at the tumour this causes damage to the cancer cells and they die. this is called radiotherapy

 by using a contrast medium. eating a Barrium meal allowes a scan of the stomach 

 they carry more information and have a small range. (absorbed more by the air)they spread out less in the air

1- antenna produces em waves by oscillating electrons at a known frequency 2- this produces a wave as the same frequency as the current 3- this wave induces a current in the receiver which has the same frequency as the wave 

 State the type of electromagnetic waves in communication 

 They have a strong signal and don’t  spread out they can penetrate the atmosphere

 why are microwaves used for TV communications and radio signal? 

 why are radio waves less than 1 m used for tv signals 

range is limited to areas around transmitter 

why are radio waves of wavelengths 1-100m used by local radios 

why are radio waves longer than 100m used by national or international radio 

 Made out of thin glass, light reflects of the surface, transmit info using light, and infrared

 Carry more info, as it has a short wavelength and more secure

 film camera, digital camera, sunlight is made from all the wavelength of light

 visible light, infrared, microwaves, radio waves 

 what are the low frequency electromagnetic radiation? 

 to carry radio phone  TV signal, can penetrate and heat object

 Communication-  example, phone signal/ satellite signal, can heat food and vibrate food molecules  

 optical fibre -  transmit info Electric heaters

 what are in infrared  radiation used for 

 protect other parts of the body as it absorbs x-rays - this is then converted into light by a charged cable device  

p12 flashcards

Flashcards

p12 flashcards

Waves

Year 8 physics end of year