An amateur astronomer decides to build a telescope from a discarded pair of eyeglasses. One of the lenses has?
Tuesday, December 7th, 2010 at
9:21 am
An amateur astronomer decides to build a telescope from a discarded pair of eyeglasses. One of the lenses has a refractive power of 11 diopters, while the other has a refractive power of 1.1 diopters. What is the angular magnification of the telescope?
Thank you, but I tried 10 as the magnification and it says that is wrong
 |
US $81.45
1/11 meters is the focal length of the one lens.
1/1.1 is the focal length of the other lens, the longer one.
Take the focal length of the longer one and divide it by the focal length of the shorter one and get a telescope of 90 cm divided by 9 cm.
You can measure the focal length of a plus lens by focusing the light from the sun and measuring the distance.
A lens that focuses the light at 2/3 meter has a power of 3/2 diopter or +1.50 D.
A lens that will neutralize a +1.50 lens is a -1.50 lens.
(a 10 power telescope)
If she would look for a +.50 diopter lens, he could make a telescope of twice the power