Page 6 - 6-SCI-10(10)

10. Properties of Light eLearn.Punjab

• We can turn the sunlight towards dark places by the regular reflection of light with the help of a
shiny surface.

• Sunlight does not reach directly in our rooms, but we can see things in our rooms. This is because
of diffused reflection of light. The light scatters in different directions when it shines on dust
particles.

• We can see things just before the sunrise and just after the sunset due to the diffused reflection
of light.

Images Formed By a Plane Mirror

A shiny surface is called a mirror. A plane mirror has a smooth and
flat surface. We see images in a plane mirror when light reflected by
the mirror enters our eyes. We use a plane mirror to see our faces.
We observe that;
1. The image formed by a plane mirror is upright (straight upward).
2. The image is equal in size to the object.
3. The image is laterally inverted. It means your right becomes left

in the image.
4. The image in the plane mirror is virtual. It means the image

disappears on removing the object.
5. The image is as far behind the mirror as the object is in front of it. Fig.10.6: Reflection in a plane mirror

Ray Diagram For Light Reflected From a Plane Mirror

Take a sheet of white paper and fix it on a drawing board. Draw a line MR on the sheet and put
a plane mirror vertically along the line. Now fix a pin O, serving as the object before the mirror
(Fig.10.7).
View the image I of pin O from left side of the object pin and fix two pins P and Q in such a way that
both of these pins and image I lie in the straight line. Now view the image from the right of the pin
O and fix two pins S and T in the same way.
Remove all the pins and put cross (x) to mark each pin hole. Draw lines PQ and ST beyond the
mirror line MR till both lines intersect each other. Draw a vertical line from O to I which meets MR
at N. Also join O to the points A and B where lines PQ and ST meet the line MR. Measure ON and
IN. ON is the distance of the object from the mirror and IN is the distance of the image from the
mirror. Both will be equal.

6