Question

Which property of a reflecting telescope determines its light-gathering or light-collecting power?

• A. Elimination of extraneous light.
• B. Size of the primary lens.
• C. Obstruction of ultraviolet rays.
• D. Apprehending white light better than any other color.

Answer 1

The correct option is B

Size of the primary lens.

Reflecting telescope:

1. A device that employs lenses, curved mirrors, or a combination of the two to observe distant objects, or a variety of technologies that use nonparticulate radiation to observe distant objects via emission, absorbance, or ability to reflect is called a telescope.
2. Reflecting telescopes have quite a number of benefits over refractors. The reflected light is not vulnerable to aberration since it does not disperse in step with wavelength. The reflector's telescope tube is also shorter than that of a refractor of the same diameter, decreasing the tube's expense.
3. The diameter of the objectives (the primary lens that gathers and focuses light) of an optical telescope is related to its light-gathering power, and therefore the region of the destination is proportionate to its energy strength.
4. The broader the target, the much more light the telescope catches and hence the finer information it produces. The primary lens's size is an optical telescope feature that influences its light-gathering capability.

Therefore, option B is the correct choice.