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Name Form Current Thinking hiko Light and Energy Feedback Feedforward What result are you going to aim for in your theory test? (Circle below) A M E Have you done the following steps to help you achieve your goal? Task Read through my notes Completed my homework book Marked my homework book Completed the crossword Completed glossary list Completed background reading Completed some practice questions Asked the teacher at least one question you are unsure about Completed minimum of one study technique: Concept map Brief notes Keyword flipcards Mix n Match Spider Map Mnemonics Acronyms Did you achieve your goal? (circle) YES NO Can you set 3 goals for the next topic? (Including a goal for your bookwork) 1) _________________________________________________________ 2) _________________________________________________________ 3) _________________________________________________________ Specific Learning Outcomes By the end of this topic you should be able to 1. Know about electrical charges, conductors and insulators, recognise circuit symbols and distinguish between series and parallel circuits. 2. Define current / voltage (simple terms) and describe how they are distributed and measured in series and parallel circuits. Demonstrate how to construct a simple circuit and take measurements from electrical meters. 3. Understand the ideas of power and resistance. 4. Understand the properties of magnets and how electromagnets work. Glossary of Terms Static electricity_______________________________________________________________________ Current electricity_____________________________________________________________________ Conductor____________________________________________________________________________ Insulator_____________________________________________________________________________ Negatively charged_____________________________________________________________________ Positively charged______________________________________________________________________ Circuit_______________________________________________________________________________ Electrons_____________________________________________________________________________ Cells________________________________________________________________________________ Terminal_____________________________________________________________________________ Repel________________________________________________________________________________ Attract_______________________________________________________________________________ Protons______________________________________________________________________________ Series circuit__________________________________________________________________________ Parallel circuit_________________________________________________________________________ Potential energy_______________________________________________________________________ Current______________________________________________________________________________ Energy supplier _______________________________________________________________________ Component __________________________________________________________________________ Ammeter ___________________________________________________________________________ Ampere _____________________________________________________________________________ Direct current _________________________________________________________________________ Alternating current ____________________________________________________________________ Voltage ______________________________________________________________________________ Voltmeter____________________________________________________________________________ Joule ________________________________________________________________________________ Electrical force field ____________________________________________________________________ Fuse ________________________________________________________________________________ Resistance___________________________________________________________________________ Resistor ____________________________________________________________________________ Rheostat ____________________________________________________________________________ Ohm ______________________________________________________________________________ Power ______________________________________________________________________________ Watt ______________________________________________________________________________ Magnetic field ________________________________________________________________________ Compass ____________________________________________________________________________ North pole ___________________________________________________________________________ South pole___________________________________________________________________________ Magnetized __________________________________________________________________________ Unlike poles _________________________________________________________________________ Like poles ____________________________________________________________________________ Electromagnet ________________________________________________________________________ Electric motor ________________________________________________________________________ CT1 Charge What happens to two charged rods held near each other if they have: a) the same charge_____________________________________ b) a different charge____________________________________ What charge is left on a material if it has been rubbed and: a) looses electrons_____________________________________ b) gains electrons______________________________________ Which of the following are conductors and which are insulators? a) copper_____________________________ b) plastic _____________________________ c) steel _____________________________ d) air e) wood _____________________________ ____________________________ f) salt water _________________________ Energy Changes Give an example of a situation where electrical energy is changed into: a) sound energy ___________________________________________ b) light energy ____________________________________________ c) heat energy _____________________________________________ d) kinetic energy ___________________________________________ CT2 Circuit symbols Symbol 1 Complete this symbol table. Component Function Light bulb To measure current in a circuit Give three rules to be remembered when drawing circuit diagrams. _____________________________________________________ _____________________________________________________ _____________________________________________________ CT3 1.The diagram shows a simple electrical circuit. Draw a circuit diagram for this set up. 2. Draw these circuit diagrams: a) A farmyard torch has 4 cells in series in its case with a bulb and a switch b)i) A circuit which contains three cells in series with a bulb and a rheostat. ii) Which component could be used to dim the light of the bulb?_______________________ b) Two lamps are to be placed in parallel branches with a cell, but one is to have a rheostat connected in series with it so that it may be dimmed, while the other has an ammeter in series with it and a voltmeter in parallel across it. c) A circuit containing a battery and two branches with a bulb in each. Add three switches that will allow you to turn off a) both bulbs b) each bulb separately CT4 Explain in your own words the difference you can see between a series circuit and parallel circuit ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ What are the advantages of a parallel circuit compared to a series circuit? Use the example of Xmas tree lights. ___________________________________________________________________________ ___________________________________________________________________________ CT5 Current A Current is a flow of ___________through a circuit. An ampere is the correct name for an _________. An amp has the symbol ___________. Ammeters must be connected in________________ Complete these diagrams by filling in the unknown ammeter readings. a) Ammeter A reads 1.4 amp. A A1 A2 b) Ammeter A reads one amp.(all of the bulbs are identical) A1 A2 A3 A CT 6 Electric current in your home. a) What can causes an increase in the current in the wiring? __________________________________________________________ b) What happens to a wire that has too high a current going through it and what might be the result? __________________________________________________________ c) Draw the circuit symbol for the component that is used to protect your home from an electrical fire due to overloading of the electrical wiring. d) Explain how this component protects your home from an “electrical fire”. due to overloading the electrical circuit? __________________________________________________________________________________ __________________________________________________________________________________ CT7 Voltage a) What does “voltage” measure? (explain in your own words) ___________________________________________________ b) One volt is _________________ joule of energy per __________ coulomb of charge. c) Voltmeters measure voltage. List two things to remember when connecting a voltmeter into a circuit.____________________________________________________ ____________________________________________________ d) Find out the voltage used in the following: house V car V toaster V battery powered toy V electric jug V high voltage power line V Complete the diagrams, by writing the voltmeter readings onto the diagrams. The bulb without a voltmeter is using 8.0V. Voltmeter V12 reads 4.0V. The bulbs with voltmeters V12 and V13 are identical CT8 A trip to town A group of friends collected their allowance and went into town to spend it. The places they went are shown on the map. Their journey is shown on the map and also as a circuit diagram. 1. Use both diagrams to answer the questions below. a. How many went bowling?__________________ b. How many didn’t go bowling? ______________ c. How many went to the rugby game? ____________ d. How many went to the Game Zone? ______________ e. How many went over the bridge? _______________ f. How much did it cost to play bowls? ________________ g. How much was each person’s allowance? ________________ h. How much did the burgers cost? ____________________ i. How much did the Game Zone cost? ____________________ j. How much does an ice cream cost? ________________ 2. Fill in the missing meter readings on the circuit diagram above. 3. Work out the values of the meters in the circuit diagram on the right, and write them on the diagram. CT9 A test of resistance 1 Kay measured the current through two types of resistance wire (A and B) for a range of lengths These are her results: Wire A – 1.9A: 30cm Wire B – 0.3A: 60cm Wire A – 40cm 1.6A Wire B – 20cm 1.2A Wire A - 60cm 1.4A Wire A - 20cm 2.2A Wire B - 0.8A 30cm Wire B – 40cm 0.6cm 2 Complete the table below, putting her results in a sensible order. What happens to the current in the wire as the length increases? ____________________________________________________________ What happens to the resistance of the wire as the length increases? ____________________________________________________________ ____________________________________________________________ Which of the two wires has the greater resistance? __________________________________________________________ State one factor that should remain constant during the experiment. ____________________________________________________________ Calculate the resistance for wire B 20cm long. ___________________________________________________________ ___________________________________________________________ CT10 Power Complete the table below. (Don’t forget units.) Appliance Heater Laptop Computer Soldering Iron CT11 Voltage 240V Current Power 3A 14V 42W 2A 25W MAGNETISM Use a fridge magnet and find out if the following materials are attracted to a magnet, put the information into the table, label the columns: Paper clip, hair pin, tack, toothpick, rubber band, straw, paper, fabric, concrete, 5 different coins, plastic, parts of a car, bicycle or skateboard. Write a summary on the type of material attracted by a magnet! CT12 Electromagnets Ruth and Rowena are investigating electromagnets. They set up their equipment as shown in the diagram. 1 Draw a circuit diagram of their setup in the space above. 2 How could the two girls measure the strength of the electromagnet they made, using the paper clips provided? ________________________________________________________________________________ __________________________________________ 3 4. They varied the current flowing in the circuit using the rheostat. a. Plot a graph of the number of paper clips attracted versus the current, using the results shown in the table. b. What does this graph show about the strength of the electromagnet as the current increases? __________________________________________________________ Current (A) Number of paper clips attracted at 5cm 0.4 1 0.8 2 1.2 3 1.6 4 2.0 5 State three factors that Ruth and Rowena kept constant during their investigation i ___________________________________________ ii _____________________________ __________________________ iii ______________________________________________ 5. List two ways in which the girls could make a stronger electromagnet for a given current in the coil. 6. ____________________________ ii _________________________________ Give two uses for electromagnets in everyday life. i _______________________________________ ii ______________________________________ CT13 This is an example of a magnetic field around a bar magnet Draw the magnetic field around these magnets. N S N S N S S N Find 6 uses for magnets in your household. i _____________________________________________ ii _____________________________________________ iii _____________________________________________ iv _____________________________________________ v _____________________________________________ vi _____________________________________________ CT14 Revision Crossword Current Thinking Across 1. Units of resistance. 6. Device which produces electricity 8. Lets the current travel in one direction only. 9. The build up of electrical charge on an insulator.(6,11) 11. Current which travels in one direction only. 14. Circuit in which there are two or more loops. 15. A component which determines the size of the current. 16. A thin wire which melts if the current is too large. 17. Total amount of energy supplied or used per second. 18. Complete conducting loop. 19. Current carrying coil wrapped around an iron bar. 20. Object that allow electrons to travel through. 21. A variable resistor. 22. Point of attachment for wires to a battery or ammeter. 23. Negatively charged particles which orbit the nucleus. Down 2. Circuit in which all the components are in a single loop. 3. Units of energy 4. Unit of voltage 5. Used to measure the voltage gain or loss in a circuit. 7. Units of power. 10. Objects that do not allow electrons to travel through. 12. The flow of electrons around a conducting pathway 13. Current which keeps changing direction. 15. Units of current 18. Object with a magnetised needle which is free to rotate.