Light Test Flashcards
What is the ‘period’ of waves?
The amount of time it takes to get from one crest to another
What is the ‘frequency’ of waves?
the number of waves per second
What is the ‘wavelength’ of waves?
the distance from one crest to another
What is the name of the movement of waves at repeated intervals?
Periodic movement.
If the period of a ripple of a lake is half a second or 0.5 s, what will be the frequency?
2 waves/second
If a wavelength is long what does that mean for the frequency of the wave?
The frequency will be lower.
As light is a wave, does it have a frequency?
YES
Does ‘white light’ have a specific frequency?
No – that is because it is made up of 7 colours. Therefore it has different wave lengths from different colours.
What did Newton discover?
White light consists of all colours of the visible spectrum. Red, orange, yellow, green, blue, Indigo, violet. When all colours shine at once they produce white light.
Visible light
Each colour has it’s own wavelength and frequency.
What is the violet spectrum?
This is violet light that has the highest frequency therefore it has the shortest wavelength.
What is the relationship between the colours of the visible spectrum and the frequency of light waves?
Each colour corresponds to light waves with a different frequency. So, the colour we see depends on the frequency of the light waves entering our eyes.
Explain Transmission
The light passes through an object
Explain absorption
Light is transformed into heat inside an object
Explain Reflection
Light bounces off an object
What is opaque
No light passes through
What is transparent
Light passes through
What is translucent
Some light gets through
Why does green light appear green?
It reflects mostly green and absorbs other frequencies
Why white appear white?
it reflects all visible frequencies
Why do objects appear blacker out of the sun?
Black objects absorb most of the heat/light that hits them and converts it to heat.
Why does a blue object look blue in the sun?
because only blue light reflects off of it, the other ms are turned into heat
What is refraction and how does it link to light?
It occurs when alight ray bends as it passes from one material into another.
Tell me about refraction and reflection?
Both refraction and reflection involve light rays changing direction.
Why does ‘light’ traveling from air into glass block change direction?
It slows down
What happens with white light and a prism?
A prism can separate white light into the visible spectrum because different frequencies are refracted by different amounts.
What are the differences between reflection and refraction?
- Refraction involves light passing across a boundary from 1 material to another whereas reflection does not.
- Refraction involves a change in the light’s speed where as reflection does not.
What senses curve inwards?
The senses that curve inwards and are thinner in the middle are called concave.
Why is a magnifying glass ‘convex?
A magnifying glass makes objects appear larger than they really are. This is because they are convex.
What is the focal length of a lens?
The focal length of a lens is the difference from the focal point to the centre of the lens.
What type of lens is the human eye?
The human lens in the eye cause light rays to converge so it is convex.
