7.87.812 January 201210:24·7.8 understand that ionising radiations can be detected using a photographic film or a Geiger-Muller detector<<detection of radiation.pptx>>
Monday, February 20, 2012
7.8
7.4 to 7.9 plenaries
7.4 to 7.9 plenaries7.4 to 7.9 plenaries01 February 201213:09<<alpha, beta, gamma summary table.pptx>><<a,b,g and ionisation plenary questions.pptx>>
7.4 and 7.5
7.4 and 7.57.4 and 7.5 starter01 February 201210:00Tell the person next to you…
· What are the 7 parts of the electromagnetic spectrum you learnt in P3, Waves?· What are they in order of increasing frequency?
<<e-m spec.swf>>
(Note that microwaves are missing from this animation!)
Answers
· Radio waves· Microwaves· Infra Red· Visible· Ultra violet· X-Rays· Gamma Rays7.4 and 7.512 January 201210:24· 7.4 understand that alpha and beta particles and gamma rays are ionising radiations emitted from unstable nuclei in a random process· 7.5 describe the nature of alpha and beta particles and gamma rays and recall that they may be distinguished in terms of penetrating power
7.2
7.27.2 starter31 January 201211:35Tell the person next to you…
· The names of 3 subatomic particles· What properties do they have?<<atomic structure - electrons orbiting the nucleus.swf>><<sub-atomic particles - drag and drop.swf>>7.211 January 201214:49· 7.2 describe the structure of an atom in terms of protons, neutrons and electrons and use symbols such as 146C to describe particular nuclei<<Proton number and mass number.ppt>><<atomic structure of Li - mass and proton numbers.swf>>
6.8 to 6.10
6.8 and 6.9 starter09 December 201108:51Tell the person next to you…
· What's an electromagnet?· How is it different from a magnet?<<Electromagnet lifting a car.swf>>6.8 Field around current carrying conductor simulation28 November 201115:06Website:Embed code for your blog:<iframe src="http://www.walter-fendt.de/ph14e/mfbar.htm" style="border:0px #FFFFFF none;" name="myiFrame" scrolling="yes" frameborder="1" marginheight="0px" marginwidth="0px" height="800px" width="800px"></iframe>6.8 and 6.901 December 201118:04· 6.8 recall that an electric current in a conductor produces a magnetic field round it· 6.9 describe the construction of electromagnets
6.8 and 6.9 Plenary Multichoice questions01 December 201118:13<<6c Plenary Multichoice questions.pptx>>6.1001 December 201118:04· 6.10 sketch and recognise magnetic field patterns for a straight wire, a flat circular coil and a solenoid when each is carrying a currentStraight wire = Right hand grip rule
Flat circular coil
Solenoid
6.8 to 6.10 Plenary questions
6.7
6.7 starter01 December 201119:37Tell 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 strong2. The field is weak3. The field is of a constant strength - a "uniform" field
6.728 November 201115:08· 6.7 know how to use two permanent magnets to produce a uniform magnetic field pattern
· When the field lines are parallel, the field will be uniform
6.4
6.428 November 201115:07• 6.4 understand the term ‘magnetic field line’Observing the magnetic field around a bar magnet and a wiremagnetic field around a bar magnet and wire·Use iron filings to observe the magnetic field around a bar magnet· Use plotting compasses to observe the field· Use the 3D field demonstrator to observe field
6.4 Field around bar magnet simulation28 November 201115:06Website:Embed code for your blog:<iframe src="http://www.walter-fendt.de/ph14e/mfbar.htm" style="border:0px #FFFFFF none;" name="myiFrame" scrolling="yes" frameborder="1" marginheight="0px" marginwidth="0px" height="800px" width="800px"></iframe>Example:6.4 plenary questions and Earth's Magnetic Field01 December 201119:12<<Plenary questions and the Earth's Magnetic field.ppt>>
6.11
6.1101 December 201118:04·6.11 appreciate that there is a force on a charged particle when it moves in a magnetic field as long as its motion is not parallel to the fieldSolar wind creating aurora animationTimelapse of aurora
6.13
6.13 starter12 December 201116:07Practical - 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)<<Magnetic fields interacting - Force on current carrying wire.swf>>Answers
1. 2 magnetic fields:a. the uniform magnetic field created between the poles of the permanent magnetb. the magnetic field around the wire when the current flows2.a. Increase the current in the wireb. Increase the strength of the magnetic field3.a. Reverse the poles of the magnetsb. Reverse the direction of the current6.1301 December 201118:05· 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
<<FLHR practice.pptm>>6.13 FLHR simulation28 November 201115:06Website:Embed code for your blog:<iframe src="http://www.walter-fendt.de/ph14e/mfbar.htm" style="border:0px #FFFFFF none;" name="myiFrame" scrolling="yes" frameborder="1" marginheight="0px" marginwidth="0px" height="800px" width="800px"></iframe>Example:6.13 Plenary12 December 201111:55<<FLHR Animation - Force on current carrying wire.swf>>
6.6
6.628 November 201115:07·6.6 sketch and recognise the magnetic field pattern for a permanent bar magnet and that between two bar magnets
6.18
6.18 
01 December 2011
18:08
· 6.18 explain the use of step-up and step-down transformers in the large-scale generation and transmission of electrical energy
· http://youtu.be/LZKhGGBcYFI
>
6.18 answers
01 December 2011
18:08
[cid:image001.jpg@01CCE4AC.9D422F50]
[cid:image002.png@01CCE4AC.9D422F50]
[cid:image003.png@01CCE4AC.9D422F50]
6.20
6.20
01 December 2011
18:08
· 6.20 recall and use the relationship (for 100% efficiency):
input power = output power
Vp Ip = Vs Is
>
6.19 and 6.20 Plenary answers
01 December 2011
18:08
[cid:image001.png@01CCE4AC.921B9210]
a. Vs/Vp=ns/np
Vs/2=80/20
Vs=8V
b. Vs/Vp=ns/np
Vs/10=20/100
Vs=2V
c. Vs/Vp=ns/np
Vs/240=20/400
Vs=12V
d. Vs/Vp=Ns/Np
Vs/4=2000/50
Vs=160V
[cid:image002.jpg@01CCE4AC.921B9210]
2. Vs/Vp=ns/np
3/24=ns/480
ns=60turns
[cid:image003.jpg@01CCE4AC.921B9210]
a. Iron (Why? Iron is a magnetically soft material - it can be magnetised and lose its magnetism easily. This is necessary in a transformer as the magnetic field needs to change repeatedly)
b. electrical energy in the primary coil => magnetic energy in the core =>electrical energy in the secondary coil
c. dc current produces a steady magnetic field in the core. To induce a current in the secondary coils there must be a changing magnetic field in the core.
[cid:image004.jpg@01CCE4AC.921B9210]
a. Step down (because the voltage decreases)
b. Vs/Vp=ns/np
12/240=ns/1000
ns=50turns
c. P = V x I
24 = 12 x I
I = 2A
d. Power in secondary = 24W
e. Power in primary = 24W
f. P = V x I
24 = 240 x I
I = 0.1A
g. The current would be greater/double
Why?
Efficiency = Useful Pout/Total Pinx100
50 = 24/Total Pin x 100
Total Pin = 48W
P = V x I
48 = 240 x I
I = 0.2A
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