P5.2 Flashcards
What are electromagnetic waves?
Electromagnetic waves consist of oscillating electric and magnetic fields. The fields are oscillating in a direction at 90° to the direction of the wave
At what speed to electromagnetic waves travel?
3 x 10 to the power of 8 m/s
What is a transverse wave?
A wave that oscillates perpendicular to its travel
What is a longitudinal wave?
A wave that oscillates in the direction of the wave.
How do you calculate frequency?
Wave speed / wave length
What are some uses of electromagnetic waves?
In a microwave oven, the water and fat in food absorb the microwaves, which heats up the outside of the food. Conduction transfers energy to the middle.
Your phone communicates with microwaves
Infrared radiation cooks food in a grill or oven. Infrared from a radiator can heat you by transferring energy to a thermal store.
Lasers in CDs, DVDs, and Blu-ray Discs™ use visible light.
What can ultraviolet waves be used for?
Killing bacteria in water (sterilises it)
What can x-rays do?
Kill skin cancer cells or other cancer cells
What can gamma rays be used for?
They can kill cancer cells and also kill bacteria on food
Why are ultraviolet waves dangerous?
They can damage the DNA on the cells of your skin. The cells can grow very rapidly and cause skin cancer. If you’re spouse your eyes to ultraviolet, you can develop cataracts and which make your corneas cloudy.
Why are x-rays dangerous?
They can also damage cells and cause cancer
Why are gamma rays dangerous?
They can damage or kill the cells in your body.
