em spectrum (physics)

Question 1

what are electromagnetic waves

Answer 1

• Made up of oscillating electric and magnetic fields
• Transverse waves
• Do not carry electric charges
• Can travel without a medium, with the same speed of a 3.0 x 108 m/s in a vacuum

Question 2

do electromagnetic waves carry electric charges

Answer 2

no

Question 3

can electromagnetic waves travel without a medium

Answer 3

yes

Question 4

do em waves transfer energy

Answer 4

yes

Question 5

do em waves undergo reflections and refractions

Answer 5

yes

Question 6

arrange the em waves in decreasing wavelength

Answer 6

radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays

Question 7

arrange the em waves in decreasing frequency

Answer 7

gamma rays
x-rays
ultraviolet
visible light
infrared
microwave
radio waves

Question 8

arrange the em waves in increasing wavelength

Answer 8

gamma rays
x-rays
ultraviolet
visible light
infrared
microwave
radio waves

Question 9

arrange the em waves in increasing frequency

Answer 9

radio waves
microwaves
infrared
visible light
ultraviolet
x-rays
gamma rays

Question 10

uses of radio waves

Answer 10

• television and radio communication
• radio telescopes for radio astronomy to srudy radio frequencies from outer space
• Radio Frequency Identification (RFID) tag for tagging library books, items in warehouses, merchandise

Question 11

uses of microwaves

Answer 11

• microwave oven
• Wi-fi signals
• satellite communication

Question 12

disadv of microwaves

Answer 12

• heating effect (temp increases)

Question 13

uses of infrared radiation

Answer 13

• remote control
• intruder alarm
• thermal imaging (infrared camera)

Question 14

uses of visible light

Answer 14

• photography
• optical fibres in medicine and telecommunications
• LASER in medicine or engineering

Question 15

disadv of infrared radiation

Answer 15

heating effect (temp increases)

Question 16

uses of ultraviolet radiation

Answer 16

• sterilisation of medical equipment
• disinfection of water in water treatment plants
• check for counterfeit bank notes

Question 17

disadv of ultraviolet radiation

Answer 17

• prolonged exposure can lead to sunburns, premature aging and increased risk of skin cancer
• UV radiation can be ionising

Question 18

uses of x-rays

Answer 18

• medical radiology
  radiography to produce x-ray imaging to diagnose fractured bones or tooth decay
  radiation therapy to treat cancer
• industrial radiology: scan for manufacturing defects in metal parts
• scan luggage for prohibited items

Question 19

uses of gamma rays

Answer 19

• medical radiology
  gamma imaging
  radiation therapy to treat cancer
• Infdustrial radiology: scan for manufacturing defects in metal parts
• sterilisation of food/medical equipment

Note:
have the highest frequency and most energetic waves

Question 20

disadv of x-rays and gamma rays

Answer 20

• ionising in nature i.e. radiation that has the energy to remove electrons from atoms or molecules
• exposure can damage biological molecules, living cells and tissues –> cell death, mutations and abnormal cell division
• may cause cancers e.g. leukaemia and/or deformities to a developing foetus