Wave and light

7 Quantities that defines a wave

Amplitude, wavelength, frequency, period, wave speed, crest, trough

Amplitude

Height of the wave; measures energy

Wavelength

Distance between two crests or compressions

Frequency

Number of waves passing a point per second

Period (T)

Time for one full wave to pass a point.

Wave speed (v)

How fast the wave travels

Crest

Highest point of a transverse wave

Trough

Lowest point of a transverse wave

Amplitude (Symbol, unit and unit symbol)

A, meters, m

Wavelength (Symbol, unit and unit symbol)

Lambda, meters, m

Frequency (Symbol, unit and unit symbol)

f, hertz, Hz

Period (Symbol, unit and unit symbol)

T, seconds, s

transverse wave and example

Particles move up and down at right angles to the direction of the wave. Light waves, water waves.

longitudinal wave and example

Particles move back and forth parallel to the direction of the wave. Sound waves.

What type of wave is light?

Transverse, it travels as electric and magnetic fields; does not need a medium.

What type of wave is sound?

Longitudinal caused by vibrations; needs a medium to travel.

What is a mechanical wave?

A wave that transfers energy through vibrations of particles, it requires a medium to move.

Why can’t sound travel in space?

There’s no particles for vibrations to pass through.

In which state do waves travel fastest?

Solids  because particles are closely packed, so vibrations transfer energy more quickly.

What does convergent mean?

Rays or waves come together

In which state do waves travel slowest?

gases as particles are far apart

What does divergent mean?

Rays or waves spread apart

What is the focal point?

The point where light rays meet after reflection or refraction.

How does light travel?

Light always travels in a straight line through a uniform medium

What is the law of reflection?

Angle of incidence = Angle of reflection

Incident ray = incoming light

Reflected ray = outgoing light

Normal line = 90 degrees to the surface

How do you measure angles of incidence and reflection?

Draw a normal line at 90 degrees to the mirror. Measure angle of incidence between the incident ray and normal. Measure angle of reflection between the reflected ray and normal.

What happens when light hits a flat mirror?

Light reflects evenly, the image appears upright, same size and laterally inverted

What happens when light passes through a prism?

Light refracts and splits into colours, known as dispersion

Convex Mirror

It curves outward and makes light rays diverge, producing a smaller, upright, and virtual image

Concave Mirror

It curves inwards and makes light rays converge to a focal point, forming images that can be larger or smaller depending on distance

Convex Lens

It is thinner in the middle and makes light rays diverge, forming a smaller, upright image such as lenses for short-sighted eyes.