# Homework Help: A Mirror's Reversal Property

1. Jul 21, 2004

### relinquished™

There has been this question that has been bothering me for quite sometime. It is an assignment question I failed to answer...

Can anyone explain to me in terms of light and the laws of reflection the reason why Mirrors reverse an image left-to-right?

2. Jul 21, 2004

### Njorl

They don't.

When it is in front of you, it reverses front to back, not left-right. This makes your left hand look like a right hand.

When you stand on one, it reverses top to bottom. Only when it is to your side, does it reverse left-right.

Njorl

3. Jul 21, 2004

### HallsofIvy

A mirror DOESN'T reverse anything. THAT'S why images in a mirror look peculiar. Imagine a person standing beside you stepping in front of you. In order for you to see her, she would have to turn around- i.e. reverse! Because you are used to that, when a mirror DOESN'T reverse, it looks peculiar.

Another example: look in the mirror as you are driving- everything LOOKS reversed. That's not because the mirror has reversed anything. In order to see the same thing without the mirror, you would have to turn around- reversing yourself. Using a mirror you lose that reversal you normally have.

4. Jul 21, 2004

### Gokul43201

Staff Emeritus
I think what Njorl means by "reverses front to back" is that the operation defined by 'reflection' takes P=(x,y,z) to P'=(x,y,-z) for a mirror along z=0.

5. Jul 22, 2004

### relinquished™

thanx guys.. you've helped me out ^_^