Yr 11 Physics – Area of Study 2 – How do electric circuits work? Chapter 4 – Practical electrical circuits - Workplan

LessonReading

& Cornell notes

Content Question

116/2

p. 124- 127 Circuit rules 4.1 Q 1-2

Edrolo – Effective Resistance

219/2

p. 128- 132 Series & parallel circuitsWorksheet

4.1 Q 3-7

320/2

p. 134- 136 Power in series and parallel circuits, short circuitsworksheet (Social stream)

Electricity questions series and parallel 200218.doc

4.1 Q 8-9

423/2

p 138-140 Voltage dividers 4.2 Q 1 - 2

Edrolo – Components

5 & 626/2

p.141 - 147 Transducers, sensors and the potentiometer 4.2 Q 3 -10

727/2

Edrolo - Domestic Electricity

Edrolo – Domestic Electriciyt

4.3 Q 1-10

Extension – Electricity Exam type questions (social stream)

SAC 2/3 Test Chapters 3 & 4 Chap 4 Review Q 2, 5, 7, 9, 10, 13, 16, 17, 19

Lesson 1 OutcomeBy the end of the lesson you will be able to recognise circuit symbols and apply circuit rules (known as Kirchoff's current and voltage laws) to a circuit

Testing Circuit Laws

Use PhET Circuit Constructor to build a circuits to test Kirchhoff's Laws

State the current circuit law (Kirchhoff’s law for current):

Consider the circuit below

Choose two wire resistors of the different size use your multimeter around the circuit to determine the current at the positions shown.

Show if the current law holds true.

State the voltage circuit law (Kirchhoff’s law for voltage):

Consider the circuit below:

Choose two resistors of the different size and use your multimeter around the circuit to determine the voltage at the positions shown.

Show if the voltage law holds true.

1. What would happen to the current values if on resistor was made larger?

2. What might happen to the voltage values if one resistor were made larger?

 

Answer all the questions from the activity

Youtube: Using Kirchoff's Laws

Try questions Q 4.1 1 -2 from the text

Read and take Cornell Notes pg 128-132 for next lesson (there will be test)

Lesson 2 OutcomeBy the end of the lesson you will be able to recognise series and parallel circuits and be able to calculate current, voltage and resistance.

Prac: Resistors in parallel Use PhET Circuit Constructor to build a circuit to test the resistance of the following combinations.

V total (V) I total (A) Effective Resistance R total (Ohms)

1. What do you notice about the effective resistance as more resistors are added in parallel?

2. What do you notice about the current?

Use your multi meter and three of the same resistors to determine the resistances of the following combinations.

Circuit Predicted Measured 

Repeat steps 2 and three with different sized resistors.

1. What is the rule for effective resistance when you have identical resistors in parallel?

2. How does the magnitude of effective resistance compare to the magnitude of the individual resistances?

Youtube: Compound circuits

Try questions Ex 4.1 Q’s 3-7

Read and take Cornell Notes pg 134-136 for next lesson (there will be test)

Lesson 3 Outcome

By the end of the lesson you will be able to calculate power in series and parallel circuits. Identify a short circuit.

Try questions Ex 4.1 Q’s 8-9

Read and take Cornell Notes pg 138-140 for next lesson (there will be test)

Lesson 4 OutcomeBy the end of the lesson you will be able to describe the function and use circuit analysis to solve a voltage divider circuit.

Test 1 - Examining a potentiometer (variable resistor)

Use the multimeter set to resistance to investigate a potentiometer.

Connect the meter across the two outside probes.Record the reading: Twist the knob, how does that effect the resistance?

Disconnect the meter and turn the knob so it can't turn any more. Connect across the outside and the middle probe.Record the reading:Twist the knob, how does this effect the resistance?

Predict what would be the reading if the meter was connect across the other end and the middle.

Investigating voltage dividers

In this activity you will investigate how voltage is divided between components in a circuit and how

this property can be used in electronic circuits.

Test 2

Build the following circuit

1. What will be the output voltage when the pot is set to 1000 ohm? (calculate)

Check by measuring

2. Change the resistance on the pot. What happens to the output voltage?

3. What is the range of the output voltage for this circuit?

4. How could you change the circuit to achieve a range from 0 - 1 volts?

Try questions Ex 4.2 Q’s 1-2

Edrolo – Domestic Electricity – watch videos and complete questions.

https://edrolo.com.au/vce-physics-units-12/2404/domestic-electricity/9/

Lesson 5 & 6

6V

R2 = 1000 Ohm

OutcomeBy the end of the lesson you will recognise how different components and transducers are used in combination with voltage divider circuits

Watch DVC video – Semiconductors, diodes and transistors

Semiconductors notes

Investigating a thermistor

In this activity you will investigate the resistance characteristics of the thermistor and then examine its use in a voltage divider.

Equipment

Thermistor

Small balloon

Beaker

Ice

Bunsen burner/ hot water jug

Digital Multi Meter

Thermometer

Connect the thermistor to some connecting wires and place it in the balloon. Put some ice blocks in a little water and immerse the thermistor in it. Measure the resistance using the DMM and the thermometer. Add a little boiling water and take another measure. Continue adding warm water, after a while you may have to pour off some of the water. Try to take lots of readings and get a reading up to as close as boiling as possible. Enter your data onto a spread sheet.

Tabulate your results on excel and graph a temperature vs resistance.

Comment on the shape of the graph and the relationship between temperature and resistance for the thermistor.

1. Use your characteristic curve and the thermistor to find the temperature of:

(a) the room

(b) water from a hot-water tap

(c) water from a cold-water tap

(d) a cup of coffee.

Thermistor QuestionsImagine your thermistor has been placed in the circuit below. The supply voltage is 6.0 V

1. When the temperature increases what happens to the voltage across R?

2. What is the total resistance for the circuit at 40C?

You now use a potentiometer in the circuit as below. In a fridge an alarm will sound if the temperature increases above 8oC.

The trigger will sound when its voltage reaches 2.0 V (assume you still have a 6 V supply)

4. Over which component should you take V-out?

5. What should be the setting on the potentiometer?

Try questions Ex 4.2 Q’s 3-10

Lesson 7Outcome

By the end of the lesson you will understand how domestic electricity is wired and used in a household.

By the end of the lesson you will be able to identify the causes, effects and treatment of electric shocks to humans in the context of household use of electricity

By the end of the lesson you will be able to describe and explain fuses, safety switches, Earthing and insulation techniques used to ensure household safety when using electricity.

Does voltage or current kill you?

https://youtu.be/9iKD7vuq-rY

Why is electricity dangerous?What happens (specifically) when you are electrocuted?

Watch this slo-mo video

Using the multimeters, compare the resistance of moist skin with dry skin

Safety switches

https://youtu.be/N9Gwf_WNoSQ

Try questions Ex 4.3 Q’s 1-10

Chapter Review Chapter 4 Q 2, 5, 7, 9, 10, 13, 16, 17, 19