Question

A student has three concave mirrors A, B, C of focal lengths 20 cm, 15 cm and 10 cm
respectively. For each concave mirror he performs the experiment of image formation for three values of
object distance of 30 cm, 10 cm and 20 cm.
Answer the following with relevant reason
(a) For the three object distances identify the mirror which will form an image equal in size to that of object.
Find at least one value of object distance.
(b) Out of the three mirror identify the mirror which would be preferred to be used for shaving purpose.
(c) For the mirror B draw ray diagram for image formation for any two given values of object distance.

Answer 1

Answer:

Three concave mirrors A, B,C

Focal length of mirror

A= 20cm;

B= 15cm

C= 10cm

Object distances for these mirrors are 30cm, 10cm and 20cms respectively.

1) Mirror c will produce image of same size as object because object is placed on c.

2) Mirror B can used as shaving mirror because when object is kept inbetween P and F we get virtual , erect and magnified image.

3) please refer attachment for Ray diagrams.