- A stun gun delivers 3 amperes of peak current in pulses lasting 80 microseconds. One pull of the trigger delivers 95 pulses in a 5 second cycle. A sustained 3 amps is more than enough to kill a person, but because it is delivered in such short bursts a stun gun is only capable of delivering intolerable pain.
- Determine the total charge delivered by the stun gun in one cycle.
- Determine the average current of the stun gun in one cycle.
- Write something.
- Write something.
- Write something completely different.
- Does more electric charge flow out of a battery or into a battery when it is in use? What about when it is being recharged? Explain your reasoning.
- What is the sign of the net electric charge on the current carrying wires in your home? Explain your reasoning.
- What happens to the electrons in a wire as they pass through a light bulb (or any other electrical device)? That is, what changes as electric current flows through a circuit?
- What is the source of the electrons when an electric current flows through a circuit?
- A typical Van de Graaff generator or Wimshurst machine used for classroom demonstrations produce electric potentials of 100,000 V or more. They make impressively large sparks that hurt like hell, but will not kill you. Household electrical outlets provide a potential difference of 120 V in the US (240 V in the UK). It almost doesn't need to be said, but one should never touch bare wires in a house or any other building. The risks are just too great. This seems like a contradiction. Why doesn't the higher voltage of a classroom demonstration come with a higher risk of death? (There are two factors at work here.)
- An average human brain has a power consumption of about 20 W.
- How much current flows within the brain as its neurons switch from resting potential (−70 mV) to action potential (+40 mV)? Hint: a watt is a joule per second, a volt is a joule per coulomb, and an ampere is a coulomb per second.
- Would you blow a fuse if you wired your brain into a 20 A circuit in a typical North American home?
- Movie trivia question: Could you power The Matrix using humans as batteries?
- The magnitude of the electric field needed to produce a spark in air (its dielectric strength) is about 3 × 106 V/m. As Benjamin Franklin showed in his famous experiment of 15 June 1752, lightning is basically a very, very large spark. A good sized bolt could travel 1 km and transfer 1,000 C of charge in half a second.
- What voltage is needed to make a typical lightning bolt?
- How much current flows along its jagged path?
- How much energy does it deliver?
- What is the power of a lightning bolt?
- Movie trivia question: Could you power a "flux capacitor" with a lightning bolt and go Back to the Future?