Simple physics question, but I can't get the right answer HELP
Favorites|Homepage
Subscriptions | sitemap
HOME > > Simple physics question, but I can't get the right answer HELP

Simple physics question, but I can't get the right answer HELP

[From: ] [author: ] [Date: 12-04-19] [Hit: ]
what is the minimum necessary aperture diameter that a telescope must have so that it can resolve the planet and the star?I keep coming up with 2.3 m, why is this not correct-Define an angle q subtended by the telescope to be the planets orbital radius, a, divided by the distance from the earth to the star,......
Astronomers have discovered a planetary system orbiting the star Upsilon Andromedae, which is at a distance 4.2 1017 m from the earth. One planet is believed to be located at a distance of 1.2 1011 m from the star. Using visible light with a vacuum wavelength of 550 nm, what is the minimum necessary aperture diameter that a telescope must have so that it can resolve the planet and the star?
______m

I keep coming up with 2.3 m, why is this not correct

-
Define an angle q subtended by the telescope to be the planet's orbital radius, a, divided by the distance from the earth to the star, r:

q = a/r

Now set this equal tothe diffraction limited angle defined by some telescope paerture diameter D at wavelength wl:

q = a/r = 1.22 wl/D ---> solve for D

D = 1.22*wl*r/a = 1.22*550x10^-9 * 1.2x10^11 /(4.2x10^17) = 2.35 m
1
keywords: get,Simple,but,answer,can,039,physics,right,question,HELP,the,Simple physics question, but I can't get the right answer HELP
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .