Help with Physics Questions?

Supamoku! The Mystery of the World – Japan TV Program broadcasting on 29th July 2010 on TBS, Japan Channel.
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Question by Anna George: Help with Physics Questions?
I need to produce a paragraph for my physics homework. The questions are
1) the reflecting telescope- what does it do and how does it use reflection
2) spearfishing- how does refraction make it difficult to fish using a spear
3) receiving tv signals when you live in a valley- how does diffraction allow this to happen

So far, I’ve got these two answers
Reflecting telescopes use curved mirrors instead of convex lenses to collect and focus light. A large concave mirror (the centre is thinner than the edges) collects and reflects the light to make an image. Once the image forms, the lens in the eyepiece magnifies the image. Reflecting telescopes are very helpful for viewing dim or dark objects. Large reflecting telescopes can see objects that are a millionth or a billionth the brightness of the faintest star that can be seen by the human eye alone.

Light refracts as it travels from the fish in the water to the eyes of the hunter. The refraction occurs at the water-air boundary. Due to this bending of the path of light, the fish appears to be at a location where it isn’t. A visual distortion occurs. Subsequently, the hunter launches the spear at the location where the fish is thought to be and misses the fish. If the hunter with the spear‘s sight is more perpendicular to the water, the amount of refraction decreases. The most successful hunters are those whose sight is perpendicular to the water. Refraction of light occurs when it crosses the boundary, visual distortions often occur. These distortions occur when light changes medium as it travels from the object to our eyes.

Any better answers? And, I need help with the third question

Best answer:

Answer by Arthur
The first two answers are good. But I would suggest deleting the text in brackets in the first as that applies to lenses, and the last two sentences in the second as repetitive.
For a full treatment of diffraction see – http://en.wikipedia.org/wiki/Diffraction

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