We say that the wavefunction of the universe always evolves unitarily as everything gets entangled. But there is a huge problem with this reasoning. A clock has to exist outside the universe for us to define unitary evolution of the universe. But there's no clock outside the universe. It is probl...

I know that when two charges are placed in a dielectric medium (say water) then the force between the charges get reduced and the force equation is $$F=\frac{q_1q_2}{(4π \epsilon_o \epsilon_r) r^2} $$ But I want to ask whether this force also depend on the configuration of the charges inside the ...