A simple circuit contains two resistors in parallel, connected to a 20V source. What power is being provided by the source to the circuit?

A straight copper wire has a fixed voltage applied across its length. Which of the following changes would increase the power dissipated by this wire?

A battery is measured to have a potential of 5V. When connected to a wire with no resistors or other components, the voltage measured is 4.9V.

If the current through the wire is measured to be 2A, how much thermal energy is being lost per second as soon as the wire is connected to the battery?