Question

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

Answer 1

Answer:

Explanation:

 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.

Answer 2

Answer:

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.