Chapter 13 - Electromagnetic Waves

Question 1

Order the electromagnetic waves from the smallest wavelength to the longest wavelength

Answer 1

Gamma rays, X-rays, Ultra Violet rays, Visible light, Infrared, Microwaves, Radio waves

Question 2

Order the electromagnetic waves from the smallest frequency to the longest frequency

Answer 2

Radio waves, microwaves, infrared waves, visible light, ultra violet rays, x-rays and gamma rays

Question 3

What speed do electromagnetic waves travel at?

Answer 3

3.0x10^8m/s (300million m/s)

Question 4

Wave speed equation

Answer 4

Wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 5

What is visible light

Answer 5

All the light you can see

Question 6

What is white light

Answer 6

All the colours of the visible spectrum are on it

Question 7

Radio waves uses

Answer 7

Broadcasting communications carrying TV signals, navigation and radar, studying the universe and astronomy.

Question 8

Are there any dangers of radio waves

Answer 8

NO DANGERS

Question 9

Microwaves uses

Answer 9

Mobile phones, satellite transmissions and cooking

Question 10

Dangers of microwaves

Answer 10

Heats up a liquid, water molecules vibrate when heated, mobile phone can raise your temperature.

Question 11

Infrared radiation uses

Answer 11

Thermal imaging, television remite controls, short range communication.

Question 12

Infrared radiation dangers

Answer 12

Heat up your skin causing skin burns

Question 13

Visible light uses

Answer 13

Vision, photography, illumination

Question 14

Visible light dangers

Answer 14

Bad for your eyes and potentially damage it

Question 15

Ultra violet uses

Answer 15

Sun tan beds,security markers for cash, fluroscent lamps

Question 16

Ultra violet damages

Answer 16

Damage skin from the sun, you can get sunburned and it may cause skin cancer.

Question 17

X-rays uses

Answer 17

Medical x-rays, airport security cameras

Question 18

Gamma rays uses

Answer 18

Sterilising equipment, detect cancer and treat it, radioactive tracers

Question 19

Dangers of gamma rays and x-rays

Answer 19

These rays can pass through substances and knock electrons out of atoms in the substance. This is called ionisation.

Question 20

How are do carrier waves work?

Answer 20

1. An oscillator supplies carrier waves to the transmitter in the form of an alternating current.
2. Audio signal is supplied to the transmitter where it’s ued to modulate the carrier waves.
3. The modulated carrier waves from the transmitter are supplied to the transmitter aerial.
4. When the radio waves are absorbed by a receiver aeriel, they induce an alternating current in the receiver aerial, which causes osciallations on the reciever.
   5.