________________________________________ Faraday's Lab animation 28 November 2011 15:06 > Website: http://phet.colorado.edu/en/simulation/faraday Embed code for your blog: 
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Monday, January 30, 2012
6.15
________________________________________ 6.15 starter 01 December 2011 18:08
· What’s the motor effect?
· "If there’s a magnetic field perpendicular to a current in a wire, the wire moves in a direction perpendicular to the field and the current" (FLHR)
· So what about if we move a wire in a magnetic field? What happens in the wire?
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· When we move a wire in a magnetic field, a current is induced in the wire 6.15 01 December 2011 18:08
· 6.15 recall that a voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it; also recall the factors which affect the size of the induced voltage
[cid:image001.png@01CCDF29.5D4EA4B0] [cid:image002.jpg@01CCDF29.5D4EA4B0] >
> 6.15 Practical - model answers 17 January 2012 14:33
· If you...
· Push the North pole of the magnet into the coil A negative current flow shown by a negative deflection on the ammeter
· Keep the magnet stationary within the coil No current
3. Pull the North pole of the magnet out of the coil A positive current
4. Push the South pole of the magnet into the coil A positive current
5. Push the North pole of the magnet slowly into the coil A smaller negative current
6. Push the North pole of the magnet quickly into the coil A larger negative current
7. Change the coil for one with more turns of wire and push the North pole of the magnet into the coil A larger negative current
8. Push the North pole of a neodymium (strong) magnet into the coil A larger negative current
9. Move the magnet in and out of the coil repeatedly. What sort of current is this? An alternating current 6.15 Plenary answers 16 January 2012
· Explain carefully how you can induce a current in a wire (3 marks)
· State 3 ways you can increase the size of this induced current (3 marks) Answers
· The wire must be perpendicular to a magnetic field
· The wire and magnetic field must move relative to each other – the wire must “cut” through the magnetic field lines/lines of magnetic flux as it moves
· A current is induced in the wire. The induced current is perpendicular to both the field and the motion
· Increase the strength of the magnets
· Increase the speed of the relative motion
· Use a coil of wire instead of a single piece of wire 
· What’s the motor effect?
· "If there’s a magnetic field perpendicular to a current in a wire, the wire moves in a direction perpendicular to the field and the current" (FLHR)
· So what about if we move a wire in a magnetic field? What happens in the wire?
>
· When we move a wire in a magnetic field, a current is induced in the wire 6.15 01 December 2011 18:08
· 6.15 recall that a voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it; also recall the factors which affect the size of the induced voltage
[cid:image001.png@01CCDF29.5D4EA4B0] [cid:image002.jpg@01CCDF29.5D4EA4B0] >
> 6.15 Practical - model answers 17 January 2012 14:33
· If you...
· Push the North pole of the magnet into the coil A negative current flow shown by a negative deflection on the ammeter
· Keep the magnet stationary within the coil No current
3. Pull the North pole of the magnet out of the coil A positive current
4. Push the South pole of the magnet into the coil A positive current
5. Push the North pole of the magnet slowly into the coil A smaller negative current
6. Push the North pole of the magnet quickly into the coil A larger negative current
7. Change the coil for one with more turns of wire and push the North pole of the magnet into the coil A larger negative current
8. Push the North pole of a neodymium (strong) magnet into the coil A larger negative current
9. Move the magnet in and out of the coil repeatedly. What sort of current is this? An alternating current 6.15 Plenary answers 16 January 2012
· Explain carefully how you can induce a current in a wire (3 marks)
· State 3 ways you can increase the size of this induced current (3 marks) Answers
· The wire must be perpendicular to a magnetic field
· The wire and magnetic field must move relative to each other – the wire must “cut” through the magnetic field lines/lines of magnetic flux as it moves
· A current is induced in the wire. The induced current is perpendicular to both the field and the motion
· Increase the strength of the magnets
· Increase the speed of the relative motion
· Use a coil of wire instead of a single piece of wire
6.13
________________________________________ 6.13 starter 12 December 2011 16:07 Practical - the current balance
· Use a current balance to investigate what happens when a current flows in a magnetic field
· How many magnetic fields are created by this apparatus?
· How could you make the wire move further? (2 ways)
· How could you change the direction the wire moves in? (2 ways)
> Answers
1. 2 magnetic fields:
a. the uniform magnetic field created between the poles of the permanent magnet
b. the magnetic field around the wire when the current flows
2.
a. Increase the current in the wire
b. Increase the strength of the magnetic field
3.
a. Reverse the poles of the magnets
b. Reverse the direction of the current 6.13 01 December 2011 18:05
· 6.13 use the left hand rule to predict the direction of the resulting force when a wire carries a current perpendicular to a magnetic field
[cid:image001.png@01CCDA83.C3807B50]
> 6.13 FLHR simulation 28 November 2011 15:06 Website: http://www.walter-fendt.de/ph14e/lorentzforce.htm Embed code for your blog: Example: http://maddog11physics.posterous.com/68-field-around-current-carrying-conduct... 6.13 Plenary 12 December 2011 11:55
> 
· Use a current balance to investigate what happens when a current flows in a magnetic field
· How many magnetic fields are created by this apparatus?
· How could you make the wire move further? (2 ways)
· How could you change the direction the wire moves in? (2 ways)
> Answers
1. 2 magnetic fields:
a. the uniform magnetic field created between the poles of the permanent magnet
b. the magnetic field around the wire when the current flows
2.
a. Increase the current in the wire
b. Increase the strength of the magnetic field
3.
a. Reverse the poles of the magnets
b. Reverse the direction of the current 6.13 01 December 2011 18:05
· 6.13 use the left hand rule to predict the direction of the resulting force when a wire carries a current perpendicular to a magnetic field
[cid:image001.png@01CCDA83.C3807B50]
> 6.13 FLHR simulation 28 November 2011 15:06 Website: http://www.walter-fendt.de/ph14e/lorentzforce.htm Embed code for your blog: Example: http://maddog11physics.posterous.com/68-field-around-current-carrying-conduct... 6.13 Plenary 12 December 2011 11:55
>
Monday, December 12, 2011
6.8 and 6.9
6.8 and 6.9 starter
09 December 2011
08:51
Tell the person next to you…
· What's an electromagnet?
· How is it different from a magnet?
<<Electromagnet lifting a car.swf>>
6.8 and 6.9 starter 2
09 December 2011
08:51
<<Concept Cartoons - Electromagnet.ppt>>
6.8 Field around current carrying conductor simulation
28 November 2011
15:06
6.8 and 6.9
01 December 2011
18:04
· 6.8 recall that an electric current in a conductor produces a magnetic field round it
· 6.9 describe the construction of electromagnets
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| <<Electromagnets.ppt>> | <<magnetic field around wire and a solenoid.swf>> |
6.8 and 6.9 Plenary Multichoice questions
01 December 2011
18:13
<<6c Plenary Multichoice questions.pptx>>
6.10
6.10
01 December 2011
18:04
· 6.10 sketch and recognise magnetic field patterns for a straight wire, a flat circular coil and a solenoid when each is carrying a current
Straight wire = Right hand grip rule
Flat circular coil
Solenoid
6.7
6.7 starter
01 December 2011
19:37
Tell the person next to you…
1. If the field lines are close together, what does this tell you about the field?
2. If the field lines are widely spaced, what does this tell you about the field?
3. If the magnetic field lines are parallel to each other, what does this tell you about the field?
Answers
1. The field is strong
2. The field is weak
3. The field is of a constant strength - a "uniform" field
6.7
28 November 2011
15:08
· 6.7 know how to use two permanent magnets to produce a uniform magnetic field pattern
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· When the field lines are parallel, the field will be uniform
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