Date: Mon, 8 Feb 1999 12:10:08 -0600 (CST)
To: QandQ@MathCentral.uregina.ca
Subject: Satellite dishes
Name: Katherine
Who is asking: Student
Level: Secondary
Question:
I have read your information on 'Why are satellite dishes parabolic", and I know the reciever should be placed at the focus of the parabola. Could you test this with lights beams and a parabolic mirror, or would light beams behave differently. Thanks.
Hi Katherine
Yes you can locate it by using the light beams. They behave the same way. Good idea! This is exactly how a reflecting telescope works. The light from a distant object is reflected off a parabolic mirror and concentrated at the focus. The mirror behind the headlight of a car is also parabolic, but here the light source is at the focus and the light is reflected off the mirror in parallel rays.
Cheers,
Jack and Harley
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