Q.1 How does the light travel from one point to the other?
Q.2 Give one example of living thing which emits light ?
1)Light gets from one place to another because of what it is....it
is a WAVE. Just like the way a water wave moves across the
ocean towards the shore. In the case of water, some energy
in the form of wind, or a passing boat, or a rock dropping into
it starts the wave in motion, and it continues waving until something
stops it. In the case of light, some energy in the form of electricity,
or heat, or nuclear fusion (the Sun) generates the wave, and it
continues waving until something stops it.
Well, we know in the case of water that the thing waving up and down
is the water. What is waving with light? That is where light is unique.
Light is an 'electromagnetic wave'. That simply means it is made up
of an electric component and a magnetic component. Remember from
basic physics that a moving electric field creates a magnetic field,
and a moving magnetic field creates an electric field. So light starts
as a moving electric field, which creates a moving magnetic field,
which creates a moving electric field...and on and on....all the time
moving forward. It is best described as a series of self-propagating
electromagnetic fields. Because it keeps itself going, it doesn't
need any medium to move through the way a water wave needs water
or a sound wave needs air. Light can move through water or air or
a vacuum with equal ease. And it will keep moving until something
stops it. It is just an endless series of electric fields and magnetic
fields moving up and down and side to side. The forward motion of
the wave is always perpendicular to the direction of motion of the
undulating fields. And its speed is always very fast. The speed of
a light wave is the fastest thing in the universe.
1) According to the the Particle Theorem of Light, light is composed of particles which travel in a straight line at a very high speed. So, light always travel in a straight line between any two points.
2) Animals which emit light of their own are called Bioluminescence animals. Examples are firefly, anglerfish, etc.
Hope this helps!!