Paper 1 - Dangers And Uses Of Electromagnetic Waves

Question 1

What are the most dangerous type of wave ?

Answer 1

The highest frequency waves are the most energetic and the most dangerous waves.

Question 2

X rays and gamma rays dangers

Answer 2

Can cause mutations to the DNA in body cells, this may kill the cells or cause cancer

Question 3

Uses of gamma rays

Answer 3

• to sterilise food and medical equipment by killing microorganisms
• in scanners to detect cancer. Chemical that emits gamma rays injected into the blood, collects in cancer cells. A scanner outside the body locates the cancer by finding the source of the gamma rays. (Gamma rays can pass through all the materials in the body)
• to treat cancer (radiotherapy)

Question 4

Uses of X - rays

Answer 4

• to look inside objects, including medical x-rays to look inside the body
• in airport security scanners to see what people have in their luggage

Question 5

Dangers of ultraviolet

Answer 5

UV in sunlight can cause damage to skin cells, causing sunburn. Over time exposure to UV can cause skin cancer. UV can also damage the eyes leading to eye conditions.

Question 6

Uses of ultraviolet

Answer 6

• to detect security marks made by using special pens
• inside flourescent lamps, a gas inside produces ultraviolet radiation when an electric current passes through it. Coating on the side of glass absorbs the ultraviolet and emits visible light
• to detect forged banknotes (real notes have markings that glow in UV)
• to disinfect water

Question 7

Uses of visible light

Answer 7

• allows us to see, lights up rooms and streets, buildings and roads (illumination)
• photography

Question 8

Dangers of infrared. What energy does it emit (hint)

Answer 8

Infrared radiation transfers thermal energy. Too much infrared radiation can cause skin burns

Question 9

Uses of infrared radiation.

Answer 9

• in cooking (grills and toasters) absorb radiation and heat up
• to make thermal images, used by police and rescue services.
• used in short range communications, such as between laptops or other small computers
• in remote controls for TV and other appliances where the signal only has to travel a short distance.
• to send information along optical fibres
• in security systems such as burglar alarms to detect people moving around. E.g. breaks infrared beam or detects body heat

Question 10

Dangers of microwaves

Answer 10

Heat water - can heat the water inside our bodies causing cell damage or death.

Question 11

Uses of microwaves

Answer 11

• in mobile phones and to communicate by satellite transmissions.
• for cooking (microwave ovens) as transfer energy to the food

Question 12

Uses of radio waves

Answer 12

• Broadcasting TV and radio programmes
• communicating with ships, aeroplanes and satellites
• controllers on the ground communicate with spacecraft using radio waves.

Question 13

What is flourescence ?

Answer 13

Some materials absorb ultraviolet radiation and re-emit it as visible light, e.g. when It is shined upon the material.

Question 14

How can we focus x - rays

Answer 14

Change in speed minor when entering new materials so can only be focused using several metal lenses together