Topic 5- Light + Electromagnetic Spectrum

Question 1

What type of wave are em waves?

Answer 1

Transverse - particles oscillate perpendicular to the direction of travel of the wave. They travel at the same speed in a vacuum

Question 2

What is the EM spectrum in terms of waves?

Answer 2

A continuous range of wavelengths, you can have a wave that behaves like a radio wave + microwave

Question 3

What part of the EM spectrum can humans detect?

Answer 3

Only visible light

Question 4

Describe the wavelength on the EM spectrum

Answer 4

Longest wavelength at top (radio) shortest wavelength at bottom (gamma).

Question 5

Describe the frequency on the EM spectrum

Answer 5

Lowest frequency at top (radio) highest frequency at bottom (gamma)

Question 6

Describe the energy on the EM spectrum

Answer 6

Lowest energy at top (radio) highest energy at bottom (gamma)

Question 7

How are radio waves produced?

Answer 7

An alternating current or oscillations in electrical circuits is applied to transmitter which produces radio waves at same frequency as alternating current

Question 8

How are radio waves detected?

Answer 8

A radio wave hits an aerial + causes an alternating current in the circuit as the same frequency as the radio waves

Question 9

What are some uses of radio waves?

Answer 9

Radio, tv, communications

Question 10

What are some uses + dangers of micro waves?

Answer 10

Cooking food, mobile phones . Internal heating of body cells

Question 11

What are some uses and dangers of infrared waves?

Answer 11

Thermal imaging. Remote controls. Cooking food. Burns skin cells

Question 12

What are some uses and dangers of visible light?

Answer 12

Vision, photography, lighting. Damage your retina

Question 13

What are some uses and dangers of UV light?

Answer 13

Disinfecting water, detecting forged bank notes. Damages skin cells + eyes

Question 14

What are some uses and dangers of X - rays?

Answer 14

Detection + treatment of cancer. Mutation of cells leading to cancer.

Question 15

What can changes to atoms + nuclei do?

Answer 15

Generate waves of any frequency

Be caused by the absorption of waves of any frequency

Question 16

What is the acronym for order of the EM spectrum?

Answer 16

Ruby
Makes 
Indian 
Vindaloos 
Using 
Xtra 
Garlic

Question 17

When a wave meets a boundary between two materials (a material interface) what happens?

Answer 17

Wave can either:
Be absorbed by second material- wave transfers every to materials energy stores
Be transmitted through second material - wave carries on travelling
Be reflected - Ray is sent back from material, happens on glass

Question 18

What do all em waves transfer?

Answer 18

Transfer energy from source to an absorber. Eg when you wean yourself by electric heater, infrared waves transfer energy from the thermal energy store of heater(source) to your thermal energy store (absorber)

Question 19

What’s the danger with high frequency em waves?

Answer 19

Higher the frequency, the more energy it transfers and so more dangerous it is

Question 20

What can changes in atoms and nuclei do?

Answer 20

Generate radiations over a wide frequency range

Question 21

What causes changes in atoms and nuclei?

Answer 21

Absorption of a range of radiations