The place you get your hair cut has two nearly parallel mirrors 6.5 m apart. As you sit in the chair, your head is 2.0 m from the nearer mirror. Looking toward this mirror, you first see your face and then, farther away, the back of your head. (The mirrors need to be slightly nonparallel for you to be able to see the back of your head, but you can treat them as parallel in this problem). How far away does the back of your head appear to be?

13 m

Explanation:

It is given that :

I got a haircut  sitting at a place having two parallel mirrors at a distance = 6.5 m apart

My head is at a distance of 2 m from the nearer mirror.

Now the light from the back of my head must go to (6.5 - 2) = 4.5 m to the back mirror.

Then it must go to 6.5 m to the front mirror and 2 m from the front mirror to my eyes.

So in order to see the back of my head, it will be = 6.5 + 2 + 4.5 = 13 m away.

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