Question

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.
B) Radio telescopes are designed to collect sound rather than light.
C) It is because radio telescopes are used in the daytime and visible light telescopes are used at night.
D) Objects that emit radio waves are always much larger than objects that emit visible light, and therefore require larger telescopes.

Answer 1

Radio telescopes are larger than visible light telescopes because they need to compensate for the longer wavelengths of radio waves to achieve the same angular resolution, and techniques like interferometry are used to enhance this further.

Step-by-step explanation:

The question concerns the size difference between radio telescopes and telescopes designed for visible light. The most accurate explanation for why radio telescopes are generally much larger than visible light telescopes is that achieving the same angular resolution with radio waves, which have much longer wavelengths, requires a much larger telescope. This is because the ability of a telescope to resolve fine detail is dependent on both the aperture of the telescope and the wavelength of the radiation being observed, with longer wavelengths presenting challenges in resolving fine detail. To compensate for the poor resolution that long radio waves would yield with a smaller dish, radio telescopes must be quite large. In addition, the technique of interferometry is often used to link multiple radio