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Physics Unit Review. Static Charge. What is the definition of static electricity? A: An excess of charges that stay in place on an object for a period of time. Is the object positively, negatively, or neutrally charged? A: Neutrally charged. How are all solid materials charged?
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Static Charge • What is the definition of static electricity? A: An excess of charges that stay in place on an object for a period of time. • Is the object positively, negatively, or neutrally charged? A: Neutrally charged
How are all solid materials charged? A: The transfer of electrons. • Materials that do not allow charges to move easily are called _________? A: Insulators • What are good conductors? A: Metals
Charge • What does the addition or removal of 6.25 x 1018 electrons produce? A: A coulomb of charge. • What machine uses friction to produce a large static charge on a metal dome called? A: Van de Graaff generator
Laws of Static Charge • A negative charge is repelled by a __________ charge. A: A negative charge. • A positive charge _________________a negative charge. A: Attracts • A charged object _______________ a neutral object. A: Attracts • A negative object attracts an unknown object. The unknown object could be ____________ or ___________. A: Neutral or positive charge • A positive object ________________ a positive object. A: Repels
Charging by Conduction or Induction • Which of the diagrams shows charging by induction? A: A and D
Voltage • What energy does electrochemical cells convert into electrical energy? A: Chemical energy • What is another name for the electric potential energy per coulomb of charge? A: Voltage
Voltage • Calculate the voltage for the diagram found below. A: 35 V
Voltage • Calculate the voltage for the diagram found below. A: 9 V
Circuits • A complete pathway that allows electrons to flow is called _________? A: Electric circuit • Any device that transforms electrical energy into other forms of energy is called ______? A: Electric load • What direction do electrons flow through a circuit? A: Negative to positive.
Circuits • State the parts of the circuit found in the diagram below. A: 2 lamps, a switch, a battery, an ammeter, and a voltmeter
Current • Define current. A: The amount of charge passing a point in a conductor every second. • Convert 2400 mA to amperes. A: 2.4 A • Convert 0.35 A to mA. A: 350 mA
Current • Calculate the current at I3. A: 4 A
Current • Calculate the current at I2, I3, and I5. A: I2 and I3 = 6A and I5 = 2A
Resistance • Define resistance. A: A property of any material that slows down the flow of electrons and converts electrical energy into other forms of energy. • State Ohm’s Law. A: R = V/I • What is the unit for resistance? A: Ohm’s
Give the value of each resistor indicated by the colour bands. • Blue, green, red A: 652 ohms • Green, orange, yellow A: 534 ohms • Brown, red, black A: 12 ohms
Ohm’s Law • Only 2.5 × 103 A of current pass through a portable CD player. If the CD player is operated by a 9.0 V battery, what is the resistance within the circuit? A: 3600 ohms
Ohm’s Law • An automobile headlight has an average resistance of 24 . Car batteries provide a potential difference of 12 V. What amount of current passes through the headlight? A: 0.5 A
Ohm’s Law • In a portable radio, 0.50 A of current are flowing through a conductor that provides 18 of resistance. What potential difference is provided by the battery? A: 9V
Series Circuit • In a series circuit, the current at one location in the circuit is ________the current at another location in the circuit. A: Equal to • If two different resistors are connected in series, the voltage across one resistor will be _________ the voltage across the second resistor. A: Different from
Parallel Circuits • If two different resistors are connected in parallel, the voltage across one resistor will be _________the voltage across the second resistor. A: Equal to • Two different resistors are connected in parallel. The current through one of the resistors will be __________ the current through the other resistor. A: Different from
Series and Parallel Circuits • Which bulbs are in parallel? A: 3, 4, and 5
Series Circuit • Calculate the missing quantities for the circuit below. A: V1 = 7.5V; R1 = 5 ohms; R2 = 3 ohms
Parallel Circuit • Calculate the missing quantities for the circuit below. A: V1 and V2 = 40 V and R1 = 2 ohms
Power • A current of 5.0 A flows through a flashlight bulb when it is connected to 6.0 V. What is the power of this bulb? A: 30 watts • A 600 W electric heater is connected to a 120 V source. What current flows through the heater? A: 5 A • 2.5 A current flows through a 100 W lamp. What is the voltage across the lamp? A: 40 V
Cost of Electricity • An electric heater draws 1300 W of power. Electricity costs 10¢ per kWh. How much does it cost to operate the heater 5.0 h a day for 30 days? A: $19.50 • A dryer is used an average of 25.0 h a month. The dryer draws 45.0 A of current from a 120 V outlet. If electricity costs 8¢ per kWh, how much will it cost to operate the dryer for one year? A: $129.60