Static vs Current Circuit Elements Resistance is V / I Energy switch Make and use How to generate

This object would be:

Positively charged

Law of Charges states: (3)

1.Unlike charges attract 2.Like charges repel 3.Charged objects attract uncharged neutral objects

List 2 good conductors

Gold, copper, nickel platinum, silver

List 2 good insulators

Cotton, glass, rubber, paper, plastic, porcelain

What does grounding an object do?

Using a conducting wire to the ground, electric charges can be neutralized. It provides a path for the charge.

Draw a lamp.

(see the board)

Draw series circuit with a battery, lamp and motor.

(see the board)

Draw a parallel circuit with 2 switches, battery, and 2 lamps.

(see the board)

Draw a parallel circuit where the lamp stays on and the motor can be turned on or off independently.

(see the board)

Explain the circuit components using a metaphor (water, highway, or hallway)

Water: water held behind a dam is voltage; water flow is the current; water wheel is the load; spill-gates control the flow like a switch.

What is the unit of resistance?

ohm

What is Ohm’s Law?

R = V/I

What is a resistor used for?

To control the current in the circuit.

What is the difference between resistors and variable resistors?

Resistors regulate a certain amount of current. Variable resistors are adjustable in the amount of current they resistance.

What is the resistance of a light bulb that uses 2A in a 120V circuit.

60 ohms

A wall heater performs this energy conversion.

Electrical to thermal

A motor does this energy conversion

Electrical to mechanical

A generator does this energy conversion.

Mechanical to electrical

Why can’t an energy conversion ever be 100% efficient?

Energy is always lost to friction.

Explain how a thermocouple works.

A wire is connected in a loop (2 different metals). One side is in a cold temperature, the other is a warm temperature. The difference in temp results in the flow of electrons to try to balance the temp difference. As soon as you have electron flow, you have electricity.

How does an electrochemical cell generate electricity?

Chemical reaction

Why do you need an electrode and electrolyte?

Electrode: provides the electrons Electrolyte: passes the electrons from one electrode to the other.

What is the difference between a motor and a generator?

A motor uses electricity and a generator makes it.

How can you use a coil of wire and a magnet to generate electricity?

Pass the magnet in and out of the coil of wire. This pushes and pulls the electrons creating electricity.

Trace the path of electricity through a DC Motor.

1.Electricity enters the negative battery terminal 2.Travels through a brush 3.Enters one side of the split ring commutator 4.Goes into the armature causing it to become an electromagnet. 5.Exits other side of armature, travelling into the other side of the commutator. 6.Into in the opposite brush and out the positive battery terminal.

What is the difference between a step-up and step down transformer?

Step up = increase voltage Step down = decrease voltage

What is the purpose of a circuit breaker?

It acts as a switch to control the amount of electricity in a circuit.

What are the three wires that enter your house?

White (neutral), black (hot), and bare copper (ground)

What is a transistor?

An electronic switch in a modern digital device that can be turned off by electric signals.

List 4 methods of energy generation.

Thermoelectric (fossil fuels, biomass), windmills, solar, hydroelectric, thermonuclear