Current Electricity

Question 1

TRUE OR FALSE: Resistance of a wire decreases as its cross-sectional area decreases.

Answer 1

FALSE: as the area gets smaller, the resistance gets larger.

Question 2

TRUE OR FALSE: A 9V battery means that the electrons have 9V of current.

Answer 2

FALSE: it means it has 9V of potential difference.

Question 3

TRUE OR FALSE: Two examples of resistors or loads would be light bulbs and switches.

Answer 3

FALSE: light bulbs and heaters. (can have multiple answers)

Question 4

TRUE OR FALSE: Electrons carry energy from the battery through the load(s) and return any excess energy to the battery.

Answer 4

FALSE: all energy goes into the load. the battery gives energy to the electrons,, so there is no excess energy.

Question 5

TRUE OR FALSE: when the switch is open electricity does not flow because it is a short circuit.

Answer 5

FALSE: there is no path for the electricty to flow through. (the circuit is incomplete)

Question 6

TRUE OR FALSE: The units that make up the amp are volts divided by ohms.

Answer 6

TRUE.

Question 7

TRUE OR FALSE: Potential difference is measured with a voltmeter.

Answer 7

TRUE.

Question 8

TRUE OR FALSE: Most house wires have a plastic or rubber coatinng because they are excellent insulators.

Answer 8

TRUE.

Question 9

TRUE OR FALSE: Loads are designed to decrease resistance so electrical energy can be changed into other kinds of energy.

Answer 9

FALSE: loads are designed to add more resistance.

Question 10

Parts of a Circuit:

Answer 10

1. Source (Alternating vertical lines)
2. Wires (Connecting lines)
3. Switch (Can be opened or closed)
4. Load/Resistor (Light, Motor, Anything else= squiggle)
5. Fuse (horizontal S, kind of)

Question 11

Where do electrons move?

Answer 11

From the start of the source all the way back. It returns with no more energy.

Question 12

OHM’S LAW EQUATIONS:

Answer 12

V = I x R
I = V/R
R = V/i

Question 13

The Different Meters (3):

Answer 13

Voltmeter = Potential Difference
Ammeter = Current
Ohmmeter = Resistance

Question 14

What is V?

Answer 14

• Potential difference (Voltage)
• Amounts of energy (Batteries, etc.)
• Volts (V)
• Needs to hug whats testing. (source)

Question 15

What is I?

Answer 15

• Current
• # of electrons moving
• Measured in amps (A, ampere)

Question 16

What is R?

Answer 16

• Resistance
• Measured in ohms (Horseshoe like)
• How the load turns electrical energy into other forms of energy

Question 17

If the current is too high, there is danger of a fire starting.

Answer 17

• This is because there are too many electrons pushing to get thrugh the wire. = Heat up = Fire = Explosion