Q23 of 45 Page 302

How can you identify the three types of mirrors without touching them?

Give reasons.


The three types of mirror can either be identified by their shape or the type of image it makes of a person standing in front of it.

We will look into the mirror by going close to it:
(i) If image is of same size and erect-plane mirror.
(ii) If image is of bigger size and erect – concave mirror.
(iii) If image is of smaller size and erect – convex mirror.



More from this chapter

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21

Reena and Vani find a discarded plastic lens lying on the beach. The girls’ discuss what they learnt in Physics and argue whether the lens is a converging or diverging one. When they look through the lens, they notice that the objects are inverted.

i) If an object 25 cm in front of the lens forms an image 20 cm behind the lens, what is the focal length of the lens?


ii) Is it a converging or diverging lens?


 22

Light which is incident on a flat surface makes an angle of 150 with the surface.


i) What is the angle of incidence?


ii) What is the angle of reflection?


iii) Find the angle of deviation.


 24

What will happen when the frequency of rotation in an AC dynamo is doubled?

 1

Draw the given diagram and label the following in the diagram.


i) Incident ray


ii) Refracted ray


iii) Emergent ray


iv) Angle of refraction


v) Angle of deviation


vi) Angle of emergence