Topic 6- Electromagnetic Waves Flashcards
What type of spectrum toe electromagnetic waves form?
Continuous
Order the typed of electromagnetic radiation from lowest to highest frequency
Radio waves Microwaves Infrared radiation Visible light Ultraviolet X-rays Gamma rays
How do the speed of electromagnetic radiation differ in a vacuum and in air?
All travel at the same speed in a vacuum and in air
In which direction do waved refract when entering a fender medium?
Bend towards the normal.
What is the relation between wavelength, energy and frequency of a wave?
Longer the wave length, lower the frequency and energy
Why can infrared be damaging?
It can kill or injure skin cells as it heats them up
Why do microwave ovens heat food faster than normal ovens?
Microwaves penetrate the food and are absorbed by water molecules in the food, therefore heating it up
Where do gamma rays originate from?
Changes in the nuclei of atoms
What health effects can ultraviolet waves cause?
Skin can age prematurely + increase the risk of skin cancer
What health effects can x rays and gamma rays cause?
Ionising radiation can cause mutations in genes. Increased risk of various cancers.
What are 3 practical uses for infrared radiation?
Electrical heaters
Cooking food
Infrared cameras
What are 2 practical uses for microwave radiation?
Satellite communications
Cooking food
What are 2 practical uses for radio waves?
TV transmission
Radio transmission
What property of waves in different mediums causes refraction?
Velocity
Wave speed is slower in denser materials, causing refraction
How can radio waves create an alternating an current in a circuit?
When radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves
