CH 23

Temperature difference is a necessary condition for the flow of heat. Similarly, a voltage difference is necessary for the flow of charge.

The water flow in the pipe occurs when a difference between water levels exists. The analogous situation is a difference in voltage inducing a flow if charge.

Protons cannot move because they are bound inside the nuclei of atoms, which are more or less locked in fixed positions. Electrons in metals are free to wander, which is why they are called charged carriers.

One ampere is the electrical flow or current equal to one coulomb of charge per second.

Chemical batteries and electrical generators.

One volt means each Coulomb of charge can release one joule of energy. V= W/q. W= Vq E= Vq E= (1C)(12 V) = 12 J. Thus energy supplied to each coulomb if charge is 12 J.

Charge flows through a circuit, and voltage is established across a circuit.

Wide pipe and thick wire.

Increase electrical resistance.

Current will be halved.

Current will be halved.

Wetness decreases resistance of the body.

The round third pong is connected to the body of the appliance, which is grounded. So if the live(hot) wire accidently comes in contact with the body if the appliance, you won't receive the shock since the appliance casing is grounded by way of the round third prong.

The battery produces DC, and the generator at a power station produces AC.

This means that the current flows alternatively back and forth at a frequency of 60 Hz.

A diode acts as a one-way valve that allows electrons to flow in only one direction.

A capacitor.

This is because it is not electrons that travel, it is the electric field that travels at about the speed of light.

The electrons moving in the wire collide with metallic atoms in their path and transfer their kinetic energy to them. That is why current carrying wires become hot.

The net flow of electrons in a single direction in a conducting wire is called drift velocity.

This is a good analogy for sound, but not for electrical currents.

Electrons are already in the wire. The battery and generators are the only sources of energy.

Energy

These electrons originate from the body.

Electric power= electric current x electric voltage.

The watt and kilowatt are units of energy, while a kilowatt-hour is a unit of power.

A 100 W lamp does not use all its energy to light a room but most of the amount is lost in the form of heat. So a 100 W lamp with 90% of its energy lost as heat is less efficient than a 25 W lamp with 10% of its energy lost as heat giving the same amount of light. Therefore, the efficiency of a lamp depends on the heat emitted.

The current through the other lamp is also 1 A. That's because the electrical current has a single pathway through the circuit. This means the current passing through each bulb along the pathway is the same.

4V because the total voltage impressed across a series circuit is equal to the sim of the voltage drops across each individual bulb.

The same voltage, 6 volts.

The sum of the currents through the branches of a simple parallel circuit is equal to the current that flows through the voltage source.

When the circuit is overloaded, the fuse blows and breaks the circuit. Thus, fuse or circuit breakers are used to protect lines.