Physics EM WAVES SOUND WAVES REFLECTION/REFRACTION

EM WAVES/ SOUND/ REFLECTION/ REFRACTION/ WAVES

Wave

A disturbance caused by an oscillating source that transfers energy and information in the direction of wave travel, without transferring matter.

Transverse Wave

A wave in which the oscillations are perpendicular to the direction of energy transfer.

Longitudinal Wave

A wave in which the oscillations are parallel to the direction of energy transfer; it has areas of compression and rarefaction.

Electromagnetic Waves

Transverse waves that transfer energy from the source to an absorber.

Visible Light

The part of the electromagnetic spectrum that is detected by our eyes, with different wavelengths appearing as different colors.

Infrared Radiation

Radiation emitted by all objects due to the motion of their particles; the amount and frequency depend on the temperature and surface of the object.

X-rays

X-rays are part of the electromagnetic spectrum. They have a very short wavelength, high energy and cause ionisation.

Properties of X-rays

X-rays can be used to diagnose some medical conditions, for example in computed tomography (CT) scanning, bone fractures and dental problems. X-rays are also used to treat some conditions, for example in killing cancer cells.

The use of high energy ionising radiation can be dangerous, and precautions need to be taken to monitor and minimise the levels of radiation that people who work with it are exposed to.

Sound Waves

Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound.  The range of human hearing is about 20 Hz to 20 000 Hz.

The pitch of a sound is determined by the frequency of vibrations of the source. Its loudness is related to the size of the amplitude of the disturbance.

Sound waves can be reflected (echoes) and diffracted.

Normal

A construction line perpendicular to the reflecting surface at the point of incidence.

Reflection

When waves are reflected, the angle of incidence is equal to the angle of reflection.