Question

a object is held at 30cm in front of a convex of a focl length 15 cm. at what distance from a convex mirror should a plane mirror be held so that the images in the two images coincide each other?​

Answer 1

Answer:

Step-by-step explanation:

We are given

f = -15 cm(

u = -30 cm

and the image distance will be calculated using

1/f = 1/v + 1/u

or

1/v = 1/f + 1/u

= 1/-15 - 1/30

or

1/v = (-2 - 1)/30 = -3/30

thus, we have

v = -10 cm

now, the image formed would be 30cm behind the convex so the total distance between the object and image will be

= 30cm + 10cm = 40cm.

The plane mirror needs to placed at a distance of 20cm from the object in order for the image to coincide as it will form 20 cm behind it. The total distance would thus have to be 40cm.

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