Light and Sound Flashcards
Describe Light as a form of energy; identify light sources and opaque objects
Light is the only form of energy that is visible to the human eye. Light consists of photons, which are produced when an object’s atoms heat up. When light passes through an object - most of the light is either reflected by or absorbed by the object. For Opaque objects, it’s absorbed.
State the properties of light
The properties of light are its wavelength, frequency, energy and speed
Explain the Law of Reflection
The angle between the incident ray and the normal is called the angle of incidence. The angle between the reflected ray and the normal is called the angle of reflection.
Use the Law of Reflection with Flat and Curved mirrors
Convex Mirrors - A convex mirror is also known as diverging mirror as it diverges the incident rays after reflection
Concave Mirrors - A concave mirror is also known as converging mirror as it converges the incident rays after reflection
Explain refraction in terms of change in light speed
Refraction is the bending of light when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray towards the normal. As the light ray leaves the slower medium, it will travel at same angle it entered it on.
State that light travels at different substances
The substance where the particles are ‘packed’ differently depends on what state they are in. It is the way these substances are ‘packed’ that affects the speed at which light can move through them.
Identify Total Internal Reflection
Diamonds are one of the densest substances in the world. Light is able to enter a diamond but is reflected off multiple times before it can escape. This is why diamonds tend to “sparkle”
Total Internal Reflection is the light completely trapped within a medium
State the application of internal reflection
Light is bounced along the cables carrying information.
Describe white light as a mixture of different colours
White light is a mixture of coloured lights
Explain coloured surfaces due to the wavelengths they reflect
Some of the colours of light are absorbed. Only the colours that are not absorbed are reflected and enter our eyes. Objects that reflect all the colours in white light look white because all the colours get back to your eye. Opaque colours are the ones that aren’t reflected rather than absorbed
Cornea (Eye)
Clear tissue that covers the front of the eye
Pupil (Eye)
Opening through which light enters the eye
Iris (Eyes)
Coloured part of the eye, ,controls the amount of light entering the eye
Lens (Eyes)
Focuses light on the retina.
Retina (Eyes)
Layer of light-sensitive cells in the back of the eye which respond to light
