Light and Sound

Properties of Light

Light is a form of electromagnetic wave which can be detected by the human eye.
Light travels in straight lines and this property is used in explaining how shadows are formed.
The speed of light in vacuum is approximately 3 x 10^8 metres per second.
Reflection of light happens when light bounces off an object. The law of reflection states that the angle of incidence is equal to the angle of reflection.
Light can refract or bend when it moves from one medium to another. This bending is due to a change in the speed of light.
Converging lenses bring parallel rays of light together at a point known as the focus. Diverging lenses diverge parallel rays of light.
The colour of an object is determined by the colours of light it absorbs and the colours it reflects.

Properties of Sound

Sound is a form of longitudinal wave created by vibrating objects.
The speed of sound is slower than the speed of light; in air, it is approximately 343 metres per second.
Sound needs a medium to travel; it cannot travel through vacuum.
The pitch of a sound is how high or low it sounds, and it’s determined by the frequency of the sound wave.
Loudness of a sound is related to the amplitude of the sound waves. The larger the amplitude, the louder the sound.
Echoes are due to reflection of sound waves from a surface.
Ultrasound waves have frequencies above the range of human hearing and have various applications including in medicine and sonar.

With a good understanding of these properties of light and sound, you’ll be equipped to tackle a range of related topics and problems.