Question

5. An optician while testing the eyes of a patient keeps
a chart of letters 3 m behind the patient and asks him
to see the letters on the image of chart formed in a
plane mirror kept at distance 2 m in front of him. At
what distance is the chart seen by the patient ?​

Answer 1

Explanation:

For plane mirrors, the object distance (do) is equal to the image distance (di). That is, the image is the same distance behind the mirror as the object is in front of the mirror. If we stand a distance of 2 meters from a plane mirror, we must focus at a location 2 meters behind the mirror in order to view our image.

In this case, a chart of letters is kept 3 m behind the patient and is asked to see the letters on the image of chart formed in a plane mirror kept at distance 2m in front of her. Therefore, the total distance from the chart and the mirror is 3 m+2 m=5 m.

As the object distance and image distance are equal, the image is formed at a distance of 5 m behind the mirror. The patient is at a distance of 2m from the mirror.

Hence, the total distance covered in viewing the image of the letters on the cart is 5 m+2 m = 7 m.

Answer 2

Answer:

total distance of the object from the mirror

= 3m + 2m = 5m

we know image formed has a depth Distance = distance of object from mirror.

therefore, the image is formed at a depth of 5m inside the mirror.

therefore, the chart seen by the patient is 5m + the distance of the mirror from the patient's eye.

= 5+2 = 7m

hope it helped :)