# Homework Help: Mirror question # 2

1. Dec 12, 2007

### rhxoehwhfh

The light from a star reflects from a concave mirror with a radius of curvature of 1.70 m. Determine how far the image of the star is from the surface of the mirror.

I also don't know how to do this one either

2. Dec 12, 2007

### kudoushinichi88

-_-" Since the star is really really far away, set the distance of the object from the mirror to be at infinity. Then, draw the diagram. The last time I did these sort of diagrams is when I was 17, so I can't really help you much with the diagram...

3. Dec 12, 2007

### rhxoehwhfh

so how exactly do I have to do this T.T...

4. Dec 13, 2007

### rl.bhat

Light from the star can be taken as a paralllel beam of light. When a parallel beam of light falls on a concave mirror or a convex lens they are brought to focus at the focal length. In the cas of concave mirror focal length = half the radius of curvature.

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