Summary lesson Electricity

Summary...thus far

By Maria Woodbury

Voltage, Current, Resistance

Voltage- is the push behind the electrons moving around a closed circuit
Current- is the movement of the electrons around a closed circuit
Resistance- is the ability of materials to resist the motion of the electrons around a closed circuit.
Conductors- allow the flow of electrons to pass through them. Examples are metals (Copper) and graphite (non-metal)

OHM'S LAW

When the slope of a Current/Voltage graph is uniform, we say that the resistance is contant and is OHMIC

When the slope varies, we are dealing with a NON OHMIC resistor

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Match

Match the symbol to the quantity

• voltage

• current

• resistance

• capacitance

V

A

Ω

F

• V

• A

• Ω

• F

Multiple Choice

If the voltage of a circuit is 12V, and the the current is 6A, what is the resistance?

• 2 ohms
• 3 ohms
• 1 ohm
• 4 ohms

Multiple Choice

If the current in a circuit is 3A and the resistance is 4 $$\Omega$$ what is the voltage?

• 6V
• 8V
• 10V
• 12V

Fill in the Blank

If the resistance remains constant in a circuit, the resistor is said to be

Fill in the Blank

These materials can pass electrons through their structure

Fill in the Blank

Plastic is an example of an

Circuits

Series: there is only 1 pathway for the flow of electrons
-current does not split, voltage does
-the current is the same passing through all elements
-as the load increases, the current passing through the circuit decreases.

Circuits cont.,

Parallel circuits:
-have multiple pathways
-current splits through these pathways
-voltage across all elements is constant
-if one pathway breaks, the circuit can still work

Multiple Select

Which of the following statement is true

• The bulbs are connected in series.
• If one of the bulb breaks, no light is possible

• The more bulbs are added, the dimmer they become

• current through the whole circuit is the same

Multiple Select

Which of the following statements are true?

• current splits in a parallel circuit

• if one element is removed, the circuit can still work

• voltage splits in parallel circuits

• to calculate total resistance requires a more complicated formula

Variable Resistors

Variable resistors are used to manage current flow
The greater the resistance, the less current can flow through the circuit
We see variable resistors in light dimmers, stoves, volume settings

Fuses

Fuses are made of conducting wire of different resistance that will burn if too much current is passed through them
Some fuses burn with small currents passing through them- this is usually to protect small appliances
Some fuses allow greater currents to pass through before burning
Fuses MUST be attached in SERIES in the circuit.

Multiple Choice

These items are

• ammeters

• variable resistors

• voltmeters

• capacitors

Multiple Choice

This is a symbol for

• Circuit Breaker
• Switch
• Variable Resistor

• Capacitor

Multiple Choice

This is the symbol for

• Open switch symbol
• Ground symbol
• Battery symbol
• Closed switch symbol

Multiple Choice

This is a symbol for

• variable resistor

• an open switch

• wave resistor

• fuse

Poll

I think I am understanding Electricity

• a bit better

• well

• really well

• very poorly

Poll

How much do you agree with the following statement

"I enjoy the practical lessons the most"

• not really

• sometimes

• most of the times

• always

Poll

"I find that the behaviour of the class is better than at the beginning of the year"

• not really

• sometimes

• most of the times

• always

Poll

I feel as if we have done so many topics in the last 8 weeks

• not really

• maybe

• agree

• too many topics!

Poll

I am more confident with Physics topics than I thought I would be

• not really

• maybe

• agree

• strongly agree

Poll

I would like to have some revision classes before we break up for Easter

• not really

• maybe

• yes please

Poll

If switch A is open, and switches B and C are closed, which statement is true?

• only globe 1 will work

• only globe 2 will work

• both globes 1 and 2 will work

• neither of the globes will work