Outside the atmosphere with HST, we can get a resolving power about 10 times better than we can get with a ground-based telescope of the same 2.4 meter aperture. The light-gathering power of a telescope is proportional to its area, which is proportional to the diameter of its aperture squared. The 5m telescope collects 100 times as much light as the 0.5m telescope. A wave is a propagating disturbance. Wavelength is the distance between crests of a periodic wave.
Reflection is the bouncing of light off a polished surface.
The angle of the incident light equals the angle of the reflected light. Refraction is the bending of light as it moves through different media. A photon is a particle of electromagnetic wave energy. The X-ray photon has 500 times the energy of the visible photon. This would be in the microwave part of the electromagnetic spectrum.