Answer:
1. Electromagnetic Radiation
2. Visible light
3. Electromagnetic Spectrum
4. Wavelength
5. Frequency
6. Telescope
7. Bigger
8. Refractor telescope
9. Reflector telescope
10. Astronomical Interferometer
Explanation:
The light that we see and can not see is actually Electromagnetic radiation. It consists of various rays like X-rays, gamma, radio, IR etc. Out of the complete EM spectrum we can only see 7% i.e. the visible part of the spectrum. These waves are categorized basis their wavelength and frequency. Telescopes are used to study the EM spectrum. Bigger the opening of the telescope more light can be gathered and the image will be brighter and better. In refractor telescopes, convex lenses are used to collect the light while Reflector telescopes use concave mirrors are used to gather the light. When multiple telescopes, mirror segments are used in sync to work as one, the arrangement is called as Astronomical Interferometer.