Light as a wave Flashcards
Why do we need light?
- It helps you see things
* Plants need it for photosynthesis
Which travels the fastest light or sound?
Light travels faster sound
How does light travel?
Light travels as a wave in a straight line.
In what type of wave does light travel?
Light travels as transverse waves, like the ripples in a tank of water.
Name the major difference between light and sound waves with regards to vacuums.
Light waves can travel through a vacuum (empty space).
Sound waves cannot.
What types of substances can light waves travel through?
They do not need a substance to travel through, but they can travel through transparent and translucent substances.
How long does it take for light to travel from the sun to earth?
8 minutes 20 seconds
What is the speed of light?
300,000 km per second
How long does it take for light to travel around the world?
Less than a quarter of a second
Which travels faster, light or sound? Give two examples.
Light travels much faster than sound.
- you see lightning before you hear it
- you see a firework explode before you hear it
Define luminous objects. Give examples.
Luminous objects release light.
Examples include: sun, torch, fire
Define non-luminous objects. Give examples.
Non-luminous objects do not release their own light.
However some may reflect light - e.g. the moon.
What is the study of light called?
Optics.
What is the angle between the undulations of the wave and the direction of travel?
90 degrees
What is the amplitude of a wave?
It is the height of the wave from the top of the undulation to the bottom.
