Which of the following correctly expressed power power is work power is the rate at which work is done power is determined by mass power is determined by work in mass

Explain why electric current cannot exist if a current doesn't have a voltage source.

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

What are the north and south poles of a solenoid change with?