Posterous theme by Cory Watilo

2.11 and circuit symbols - Plenary questions

Hmwk

1. Open attached powerpoint and check your understanding

2. Answer the exam style question in your exercise book (copy out question)

For next lesson

Cheers,

Mr B

2.11 and circuit symbols - Plenary questions

26 November 2010

11:39
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2.11 Exam style question

26 November 2010

12:43
[cid:image001.jpg@01CCCF90.ADED6BC0]
· Explain the shape of the V-I graph for a filament lamp with reference to the movement of electrons in the tungsten wire and the temperature of the wire (3 marks)

Click here to download:
Chapter 31 Plenary.ppt (440 KB)
(download)

Image001

2.11

Subject: 2.11

2.11 ideal results

14 January 2011

16:20

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[cid:image001.png@01CCCF90.A38DA0F0]

2.11 notes

24 November 2010

10:15
· 2.11 describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentally

Wires and resistors
[cid:image002.png@01CCCF90.A38DA0F0]
· Ohm's Law = "I is directly proportional to V for a conductor at constant temperature"
· Wires and resistors obey Ohm's Law so we say they are "Ohmic" components

Filament lamp


[cid:image003.jpg@01CCCF90.A38DA0F0]

[cid:image004.png@01CCCF90.A38DA0F0]


[cid:image005.png@01CCCF90.A38DA0F0]

Diode
[cid:image006.png@01CCCF90.A38DA0F0]
· For a diode the graph is NOT a straight line so I is NOT directly proportional to V
· Because it does not obey Ohm's Law so we say that it is a "Non-ohmic" component

Click here to download:
V-I graphs - model results and graph.xlsx (13 KB)
(download)

(download)

2.11 practical

2.11 practical

24 November 2010

10:15
· 2.11 describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentally
>
· Build the circuit using real components
· Use a power pack to provide the 0-12V variable dc voltage
· Connect to the two bottom terminals on the 10Ω variable resistor

[cid:image001.jpg@01CCCF8A.9B2A0300]
· Vary the voltage from 12V to 0V and fill in the results table
· Switch the terminals over on the power pack and repeat for negative voltages
· Repeat the experiment using a filament lamp instead of the resistor
· "Unhide" rows 9 to 13

[cid:image002.png@01CCCF8A.9B2A0300]
· Repeat the experiment using a diode connected in series with a 10Ω resistor (the resistor you used earlier in the experiment). Measure the voltage across the diode only (not the voltage across the diode and the resistor) Just fill in results for rows 9 to 20
· Open the graph tab in the spreadsheet

[cid:image003.png@01CCCF8A.9B2A0300]
· Print out a copy / take a screen shot of the graph for your notes

Click here to download:
V-I graphs - results and graph.xlsx (13 KB)
(download)

(download)

2.9 virtual experiment

2.9 virtual experiment

11 January 2011

15:12

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Link to animation

http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc

Embed code for your blog

Circuit Construction Kit (DC Only)

Click to Run

2.9 virtual experiment v2

08 December 2011

16:57
· Open Link and Learn database on Patana site http://www.patana.ac.th/linklearn/index.asp
· Search for "croc"
· [cid:image001.jpg@01CCB98A.69E14C60]
· Click on "Crocodile Technology"
· Click run, run, OK
· Open the folder on "Teachers4students" Y:\Science\MABA\P2 Electricity\Crocodile Clips files
· Drag this file

[cid:image002.png@01CCB98A.69E14C60]

into the Croc clips window and it will open
· Mark your work with a red pen
· Drag this file

[cid:image003.png@01CCB98A.69E14C60]

into the Croc clips window and it will open
· Mark your work with a red pen.

Click here to download:
circuit-construction-kit-dc_en.jar (1.84 MB)

(download)

2.11 practical

2.11 practical

24 November 2010

10:15
· 2.11 describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentally
>
· Build the circuit using real components
· Use a power pack to provide the 0-12V variable dc voltage
· Connect to the two bottom terminals on the 10Ω variable resistor

[cid:image001.jpg@01CCCF8A.9B2A0300]
· Vary the voltage from 12V to 0V and fill in the results table
· Switch the terminals over on the power pack and repeat for negative voltages
· Repeat the experiment using a filament lamp instead of the resistor
· "Unhide" rows 9 to 13

[cid:image002.png@01CCCF8A.9B2A0300]
· Repeat the experiment using a diode connected in series with a 10Ω resistor (the resistor you used earlier in the experiment). Measure the voltage across the diode only (not the voltage across the diode and the resistor) Just fill in results for rows 9 to 20
· Open the graph tab in the spreadsheet

[cid:image003.png@01CCCF8A.9B2A0300]
· Print out a copy / take a screen shot of the graph for your notes

Click here to download:
V-I graphs - results and graph.xlsx (13 KB)
(download)

(download)

2.9

2.9 starter

08 December 2011

15:56
· Look up at the lights in the class room. Most of them are working but one of them is not.
· Do you think that the bulbs are connected in series or parallel?
· Tell the person next to you. Explain why.

Domestic lighting is wired in parallel

Why?
· If it was wired in series…

[cid:image001.png@01CCB98D.38FA3230]

...and one of the bulbs broke, all of the lights would go out


· If it was wired in parallel…

[cid:image002.png@01CCB98D.38FA3230]

...and one of the bulbs broke, the other lights would stay on

2.9 notes

08 December 2011

16:30
· 2.9 explain why a series or parallel circuit is more appropriate for particular applications, including domestic lighting
[cid:image003.png@01CCB98D.38FA3230]

(download)

2.8

2.8

24 November 2010

10:13
· 2.8 recall that mains electricity is alternating current (a.c.) and understand the difference between this and the direct current (d.c.) supplied by a cell or battery.


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d.c. sources
· cell
· battery
· dc power pack
· dc generator

a.c. sources
· mains
· ac power pack
· ac generator

2.7

Click here to download:
Electrical Power and Energy Worksheet.doc (40 KB)
(download)

· 2.7 use the relationship between energy transferred, current, voltage and time:

energy transferred = current × voltage × time

E = I × V × t

E = V x I x t

E = electrical energy [ J , Joules ]

V = voltage [ V ]

I = current [ A ]

t = time [ s ]

1,000J = 1kJ

1,000,000J = 1MJ

2.6

Click here to download:
Chapter 32 Q8 Ans.ppt (245 KB)
(download)

2.6

24 November 2010

10:12
· 2.6 recall and use the relationship:

power = current × voltage

P = I × V

and apply the relationship to the selection of appropriate fuses

P = V x I

P = Power [W, Watts]

V = Voltage [V, Volts]

I = Current [A, Amps , Amperes]

1000W = 1kW

2.6 Answers

24 November 2010

10:12
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