Upcoming SlideShare
×

# 7.2 relationship between electric current and potential difference

19,996 views

Published on

Malaysia SPM syllabus Form 5 Physics Chapter 7. Part 2: Electric Current and Potential Difference

Published in: Education
11 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• can i have a copy of this presentation pls.?

Are you sure you want to  Yes  No
• PRESENTATION IS SUPER BUT SAVING OPTION IS NOT THERE SO IT IS NOT FAIR

Are you sure you want to  Yes  No
Views
Total views
19,996
On SlideShare
0
From Embeds
0
Number of Embeds
101
Actions
Shares
0
0
2
Likes
11
Embeds 0
No embeds

No notes for slide
• Battery + Bulb in a circuit- Electric field along wires
• Battery + Bulb in a circuit- Electric field along wires
• Battery + Bulb in a circuit- Electric field along wires
• Potential difference, V=Work done, W / Charge, QOrEnergy, E/Charge, QSI unit Volt (V)
• 1 volt = 1 Joule per Coulomb
• The potential difference between A and B in a circuit is 1 Volt if1 Joule of work is doneMoving 1 Coulomb of charge From A to B
• VoltmeterMust always be connected in parallel
• AmmeterMeasures current in AmperesConnected in series with a deviceLow resistance so little effect on the current flow
• Higher potential difference, Higher Current Flow↑ V, ↑ I↓ V, ↓ IV ∝ I
• Conductors that obey Ohm’s Law – OhmicConductors that don’t obey Ohm’s Law – Non-Ohmic
• A measure of how much a conductor resists the flow of electricityGood conductor = low resistancePoor conductor = high resistance
• V = IR V = potential differenceI = currentR = resistance
• Resistance of a semiconductor decreases with temperature
• A material whose resistance becomes zero when its temperature drops to a certain value called the critical temperature
• Able to sustain large currents
• Smaller power loss during transmission
• Less heat energy wasted
• Small sized motors and generators can be used
• Magnetic levitationTrains can be made to ‘float’ on strong superconducting magnetsEliminates friction between train and track
• Magnetic Resonance ImagingUsed to determine what is going on inside a human bodyBody exposed to strong superconductor derived magnetic fieldHydrogen atoms release energy at a frequency that can be read by a computer
• Electrical cable made of superconductors increase efficiencyReduce loss of energy from heat
• ### 7.2 relationship between electric current and potential difference

1. 1. CHAPTER 7: ELECTRICITY 7.1: Relationshipbetween electric currentand potential difference
2. 2. What is potential difference? is connected to a bulb It creates an electric field along the wires
3. 3. What is potential difference? The positive terminal at P has a higher potential The negative terminal at Q has a lower potential Potential Difference, V P Q
4. 4. What is potential difference? and lights the bulb Potential Difference, V P Q
5. 5. What is potential difference?Work is done When electrical energy carried by the charges is dissipated by heat and light energy after crossing the bulb
6. 6. Potential Difference Equation Potential Work DoneDifference, Charge Or SI Unit: Joule Potential Energy Difference, Charge
7. 7. What is 1 Volt?1 Volt = 1 Joule per Coulomb
8. 8. What is 1 Volt? 1 Joule of work is done1CA B
9. 9. Measuring Potential Difference Must always be connected in parallel Voltmeter V
10. 10. Measuring CurrentMeasures current in Amperes Ammeter V Must always be connected in series
11. 11. Relationship between Current and Potential Difference
12. 12. Ohm’s LawThe electric current, Iflowing through aconductor is directlyproportional to thepotential differenceacross it if thetemperature and otherphysical conditions areconstant
13. 13. Ohm’s Law
14. 14. Ohmic Conductors and Non-ohmic ConductorsConductors that obey Ohm’s Law: Ohmic Conductors that don’t obey Non- Ohm’s Law: Ohmic
15. 15. ResistanceA measure of how much of aconductor resists the flow of electricity
16. 16. ResistanceResistance (R) is defined as the ratio ofpotential difference (V) across theconductor the the current (I) flowingthrough it.
17. 17. Disadvantage of ResistanceCauses someelectrical energy toturn into heatSo some electricalenergy is lost whentrying to transmitacross a conductor
18. 18. Advantage of ResistanceResistance allows us to use electricityfor heat and lightHeat generated from electric heatersare due to resistanceLight we get from light bulb is due toresistance of the wire - filament becomes hot and glows
19. 19. Ohm’s Law Equation = Resistance V IR Current Potential Difference
20. 20. Super ConductorResistance of a metalincreases with temperature Resistance of a semiconductor decreases with temperature
21. 21. Super ConductorA material whose resistance becomes zero when itstemperature drops to a certain value called the criticaltemperature
22. 22. Advantages of a superconductor Enables superconductors to maintain a current with no applied voltage at that temperature
23. 23. Advantages of a superconductor Able to sustain large currents
24. 24. Advantages of a superconductor Enables superconductors to maintain a current with no applied voltage at that temperature
25. 25. Advantages of a superconductor Able to sustain large currents
26. 26. Advantages of a superconductorSmall sized motors and generators can be used
27. 27. MAGLEV trainsMagnetic levitation Trains can be made to ‘float’ on strong superconducting magnetsEliminate friction between train and track
28. 28. MRI Scanner MagneticResonance Imaging Used to determine what is going on inside a human body Body exposed tostrong superconductorderived magnetic field Hydrogen atoms release energy at afrequency that can be read by a computer
29. 29. Electrical power line Electrical cable made ofsuperconductors increase efficiency Reduce loss of energy from heat
30. 30. Photo credits• Flickr / kodak-moments--high-voltage / Matthias Pastwa• Flickr / you can do it! / Eyfi• Flickr / Idea / brunkfordbraun• Flickr / Lightning May 2010 / Lightnomad• Flickr / Old Altai Analogue Multimeter / Tudedude• Flickr / RCA Porto-Arc Ammeter / Carbon Arc• Flickr / resistance begins at OHM / ChrisM70• BerndGehrmann at de.wikipedia [Public domain]/ Wikimedia Commons• Flickr / Zeus Storm from ground level / dave~• Flickr / Resistance Is Not Futile / maury.mccown• Flickr / Resistance2 / steve_Iodefink• Flickr / Failure / ‘PixelPlacebo’• Flickr / img_1628 / LacerdaGonzo• Flickr / experiments with liquid nitrogen / peletiah• Flickr / Frozen – bicycle / #AlexWitt• Flickr / Superconductor / rx8geek• Flickr / afternoon tea for nerds / bionerd• Flickr / superconducting maglev / wwu124• Flickr / morning road / Todd Klassy• Flickr / LHC magnets awaiting test / spadger• Flickr / maglev / chill