Light

I have done this powerpoint on Light for my Ace a while back, so I shall now post it here too.

So basically, light is a form of energy which our sense of sight can detect. It is made of electro-magnetic radiation and travels in a straight path. The speed of light in a vacuum is calculated to be exactly 299,792,458 m/s, which approximately 186,282 miles per second.

Light Waves

• Does not require a medium to travel on. Instead, it travels through a vacuum.
• Consists of energy in the form of electrical and magnetic fields.
• Sizes of light waves are measured by wavelengths. ( Elaborating on that later )

Primary Charateristics of Light

• Intensity
• Frequency
• Wavelengths
• Polarization
• Phase
• Orbital angular momentum

Intensity

• Measure of energy flux, averaged over the period of wave.
• Obtainable by dividing either a power or a luminous flux by a solid angle, a planar area, or a combination of the two.

Frequency

• Number of waves that pass a point in space during any time interval
• Measured in Hertz ( Hz )
• The amount of energy in a light wave is proportionally related to its frequency

Wavelengths

• We can only see electromagnetic waves.
• Each colour has different wavelengths
• Distance between any two corresponding points on successive waves

Polarization

• Expression of an orientation of the lines of electric flux in an electromagnetic field.
• When light reflect from a surface like glass, the light waves polarize, meaning that they travel along an axis usually horizontal. A vertical polarizing lens reduces the brightness of these light waves while still allowing optical information through.

Phase

• In wave motion, the fraction of the time required to complete a full cycle that a point completes after last passing through a reference position.
• Two periodic motions are said to be in a phase when corresponding points of each reach maximum or minimum displacements at the same time.