What everyone gets wrong about Gravitational Lensing

Added: 2026-05-22

[00:00:00]What phenomenon named after a Greek word for darkness describes the bending of light as it passes from one medium to another?

[00:00:07]The choices are A reflection, B diffraction, C refraction, D dispersion.

[00:00:13]The correct answer is a refraction.

[00:00:17]Refraction is responsible for why a straw in a glass of water appears bent, and it's crucial for how lenses in eyeglasses and telescopes work.

[00:00:26]Which fundamental force is responsible for holding the nucleus of an atom together, overcoming the electrostatic repulsion between protons?

[00:00:36]The choices are A electromagnetic force, B weak nuclear force, C strong nuclear force, D gravitational force.

[00:00:46]The correct answer is strong nuclear force.

[00:00:50]The strong nuclear force is one of the four fundamental forces of nature. It's incredibly powerful, but acts only over very short distances, typically within the nucleus of an atom.

[00:01:04]Which subatomic particle discovered by J. J. Thomson carries a negative electrical charge and orbits the nucleus of an atom?

[00:01:12]Pick one A proton, B neutron, C electron, D quark.

[00:01:17]The correct answer is electron.

[00:01:20]Electrons were the first subatomic particles discovered by J. J. Thomson in 1897.