Question

Select the reasons why most professional telescopes are reflectors rather than refractors.

a) A lens has to be supported only around its edges.
b) Only the front surface of a mirror has to have a precise shape.
c) Reflecting telescopes have shorter focal lengths than refracting telescopes.
d) It is easier to make a large reflecting telescope than a large refracting telescope.
e) Lenses are not subject to chromatic aberration.
f) A reflector can collect more light than a refractor.

Answer 1

Most professional telescopes are reflectors rather than refractors due to the ease of construction, support requirements, and the ability to build larger telescopes.

Step-by-step explanation:

Most professional telescopes are reflectors rather than refractors for several reasons:

A lens has to be supported only around its edges. This means that a lens must be supported at multiple points, which can introduce more sources of error and make it more difficult to achieve precise alignment. In contrast, a mirror in a reflecting telescope can be supported from the back, which simplifies the construction process.

Only the front surface of a mirror has to have a precise shape. In a reflecting telescope, only the front surface of the mirror needs to be accurately polished and shaped. This is much easier compared to a lens in a refracting telescope, where both sides of the lens have to be perfectly polished.

It is easier to make a large reflecting telescope than a large refracting telescope. Building a large refracting telescope with a large defect-free lens is technically demanding and expensive. In contrast, reflecting telescopes can be made larger because the light does not have to pass through a lens.

Answer 2

d). It is easier to make a large reflecting telescope than a large refracting telescope.

f). A reflector can collect more light than a refractor.

Step-by-step explanation:

A telescope is a device that is used to observe distant objects by the use of lenses and mirrors. It is also used to observe different distant objects by their reflection, absorption, emission or the reflection of the electromagnetic radiations.

Most of the professional telescopes are reflectors because :

1. The reflected telescope is able to receive more of the light when it reflects all the light falling on surface. And it is easier for making a large telescope rather then making large lenses for the refracting telescope. So it is easier to make large reflecting telescope than a large refracting telescope.

2. A reflected telescope receives all the wavelength of the light and it reflects all the light falling on the surfaces where it is refracted telescope that contains lenses cannot absorbs all the light and causes the chromatic aberration.