2. LIGHT, SHADOWS AND REFLECTIONS
TOPIC: LIGHT
Light is a form of energy, essential for life on
earth.
Light travels very fast-its speed is about
3,00,000km per second in air.
The distance from the sun to the earth is 1485
lakh KM.
Light travels from the sun to the earth in 8¼
Minutes
3. SHADOWS
A dark area are shape produced by an object
coming between light rays and a surface.
The shape of the shadow depends on the
shape of the object and the position of the
source of light.
Some position of the shadow may be grey or
black.
Screen is necessary to form a shadow.
4. ECLIPSES
Solar eclipses–shadow of moon falling on the
earth.
When the sun, the moon and the earth come in a
straight line, with in the middle, the shadow of the
moon may fall on some portions of the earth.
Lunar eclipses shadow of earth falling on the
moon.
In a lunar eclipse, the shadow of the earth falls on
the moon. When the sun, the earth and the moon
come in a straight line, with the earth in the middle,
the shadow of the earth falls on the moon.
5. SHADOWS AND IMAGES
A shadow is black while the image is of the same
color as the object.
A shadow is similar in shape to the object, but
shows no other details about the object.
A shadow is the area where no light falls, therefore
it is black.
An image is not only of the same shape as the
object but has all the details that the object has.
The image of an object is formed in the different
way.
An image say by a plane mirror, is formed when
light from the object reaches our eyes after
reflection from the plane mirror.
