(1)A plane mirror is commonly used as a looking glass.
(2) Plane mirrors are used in making a periscope and kaleidoscope.
Activity 9.1 [T. B. Pg. 135]
To determine the nature of the inner and outer curved surface of a spoon
Procedure:
Take a large shining spoon. Try to view your face in its inner curved surface.
→Do you get the image?
→Is it smaller or larger?
Move the spoon slowly away from your face.
Observe the image.
→How does it change?
Reverse the spoon and repeat the activity.
→How does the image look like now?
Compare the characteristics of the image on the two surfaces.
Observation:
→ Yes.
→The image formed is enlarged and erect when the spoon is closer to the face.
→As the spoon is moved slowly away from the face, the image becomes large and inverted.
When the face is very far off, highly diminished and inverted image of our face is seen.
→When the spoon is reversed, the image taméindows. by the outer surface of the spoon is virtual and diminished in size.
Now, if we move the spoon away from our face, the image moves away, however the image continues to be virtual and diminished in size.
Finally, at last the image is diminished to almost point-size.
Conclusion:
→The mner surface of the spoon acts as a
concave mator, whereas the outer a surface dows. acts as a convex mirror.