Chapter 14 Electromagnetic waves Flashcards
State all the electromagnetic waves in order from the lowest frequency to the highest.
Radio waves, microwaves, infrared radiation, visible light, ultraviolet, x-rays and gamma rays.
Are electromagnetic waves transverse longitudinal waves?
Transverse waves.
Why are gamma rays used to treat cancer?
The high energy gamma rays can be directed at cancerous tumours to kill cancer cells.
How are x-rays used?
X-rays are used to produce images to diagnose the fracture of a broken arm or tooth decay. They can be used in scanners in airports as they can penetrate through most materials.
How is ultraviolet radiation used?
It can be used in sunbeds for artificial tanning or in germicidal lamps for sterilisation in hospitals.
How is visible light used?
It is used in optical fibres for medical purposes and telecommunications.
How is infrared radiation used?
Infrared remote controllers are used to control a variety of electrical devices such as they TV.
How are microwaves used?
In the microwave oven, the microwaves cause the water molecules in food to vibrate at millions of times a second. This agitation at the molecular level creates friction which heats up the food. Satellite television uses microwaves to receive television programmes via satellites in space.
How are radio waves used?
They are used in radio broadcasting and telecommunications.
What is the effect of infrared heating?
Our skin absorbs infrared waves from the Sun, making us feel warm. Thermal blankets trap infrared waves from the Sun, which warms our body in cold weather.
What is ionisation?
It is when high energy electromagnetic waves such as UV rays, X-rays or gamma rays are able to ionise atoms and molecules, including living matter.
How can ionising radiation cause damage to the human body?
Ionising radiation can damage proteins and vital molecules found in cells. They can damage chromosomes and cause an abnormal pattern of cell division which may lead to cancers such as leukaemia. Overexposure to ionising radiation may lead to premature ageing and shortening of lifespan.
