Paper 2 EMS & Waves Flashcards
How to remember EM spectrum?
Real, Men, In, Velcro, Underwear, (are), eXtremely, Gay
What are EM waves made up of?
Oscillating electric and magnetic fields caused by alternating currents
How does long-wave radio work?
Long wavelengths that bend around the curved surface of the earth
What are Microwaves used for?
- Satellites for phones and television
- Cooking (different wavelength tp satellite waves)
What can infrared radiation be used for?
Increase or monitor temperature of an object or organism. Hotter objects are brighter
How can fibre optic cables use visible light to transmit data?
Light ray continuously reflects against the glass fibre whilst moving along it.
Why can ultraviolet radiation give you a tan?
UV radiation is emitted by sun and by fluorescent lights, being exposed to either will give you a tan.
How are EM waves used in medicine?
- Xrays are used for Xray photographs to look at bones and metal in the body
- Gamma rays treat cancer (radiotherapy)
Which types of EM waves can cause damage to the body?
High frequency waves (e.g. UV, Xray & Gamma). They transfer a lot of energy.
Why are Xrays and Gamma rays dangerous?
High frequency. Emit ionising radiation that can cause mutations, cell destruction and cancer.
What does a convex wave do to light rays?
It causes them to move together and meet at the principal focus
What does a concave lense do to light rays?
Causes them to spread out
What is the equation for magnification?
Magnification = image height / object height
How do light filters work?
They only let through colours that have particular wavelengths
What is a Leslie cube?
It is a watertight cube made of aluminium with 4 different surfaces on each of its vertical sides. E.g. black, white, shiny metal and dull metal.
