Which quantity of heat is equal to 500. joules

What is the density of the black hole

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

Describe at least two advantages and two disadvantages of using hydropower as a source of energy.