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What happens to the brightness of light emitted by a lightbulb when the current flowing through it increases?

Your friend says that a battery supplies the electrons in an electric circuit. Do you agree or disagree? Defend your answer.

How much energy is given to each coulomb of charge passing through a 6-V battery?

Is a current-carrying wire electrically charged because of the electrons moving in it?

Something gets 鈥渦sed up鈥� in a battery that eventually dies and goes flat. One friend says that current is used up. Another friend says that energy is used up. Who, if either, do you agree with, and why?

Suppose you leave your car lights on while you see a movie. When you return, your battery is too 鈥渨eak鈥� to start your car. A friend gives you a jump-start with his battery and battery cables. What physics is occurring here?

Your friend says that, when jump-starting a dead battery, you should connect your live battery in parallel with the dead battery, which, in effect, replaces the dead one. Do you agree?

An electron moving in a wire collides repeatedly with atoms and travels an average distance between collisions called the mean free path. If the mean free path is less in some metals, what can you say about the resistance of these metals? For a given conductor, what can be done to lengthen the mean free path?

Why is the current in an incandescent bulb greater immediately after it is turned on than it is a few moments later? (That鈥檚 why bulbs usually burn out just as they are being turned on.)

Only a small percentage of the electric energy fed into a common lightbulb is transformed into light. What happens to the remaining energy?