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Electricity
Unit Exam Review
Question | Answer |
---|---|
If an object is repelled by a negativly charged object, the object has/is | Negative Charge |
Describe an atom | Electrons orbit around the protons and neutrons |
As Emile touches a Van de Graaf, his hair began to stand on end and spread out. This was most likely due to | His hair strands being repelled by each other |
Emile reaches out to touch Leslie and both students feel aa sudden painful shock. This is most likly due to | A static discharge from Emile to Leslie |
The amount of current flowing through a circuit is measured in | Ahmps |
What type of meter measures only potential difference? | Voltometer |
If each cell is 1.5 volts, than four cells equals | 6 volts |
When a fuse burns out in your home it means | To much current is flowing through the circuit |
Christmas trees are wired so that if one bulb "dies", the other bulbs will remain lit. These lightbulbs are connected in _______ | Parallel |
What makes up an electromagnet? | Iron core, such as an iron nail, coil of wire, and battery |
What makes up an electrochemical cell? | Electrodes; one anode, one cathode; electrolyte |
Electrode Definition | Metals -Two different -Anode; negative -Cathode-positive |
Electrolyte Definition | Liquid or paste -Salt or acid |
What is the unput and output energy conversions for a battery? | Input-Chemical energy Output- Electrical energy |
What is the unput and output energy conversions for a Generator? | Input- Mechanical energy Output- Electrical energy |
What is the unput and output energy conversions for a Motor? | Input- Electrical energy Output- Mechanical energy |
What is the unput and output energy conversions for a Thermocouple? | Input- Thermal energy Output- Electrical energy |
What is the unput and output energy conversions for a Lightbulb? | Input- Electrical energy Output- Light energy |
Insulators- definition and examples | Does not allow electrons to flow on them ex) Rubber, glass |
Conductors- definition and examples | Allows electrons to flow on them ex) metal |
Current is... | The amount of electrons flowing |
Voltage is... | The pressure the electrons are under |
Resistance is... | The slowing of electrons in a circuit |
Using Ohms law, calculate how much current is created when 210V creates a current through a 150ohm registor | (R=V/I) I=1.4A |
What type of filament in a lightbulb would offer the most resistance? | Long, thin wire |
An electric motor has a resistance of 185ohms. It is connected to a power source that has a voltage of 120V. What is the current? | (R=V/I) I=0.65A |
An electric appliance draws 1200W of power. Electricity costs 9 cents per kWh. How much does it cost to operate the appliance 4 hours a day for 50 days? | $21.60 |
A light bulb draws 1.5A of current from a 110V generator. How much energy does the generator produce? | (P=I/V) 165W |
What is a variable resistor? | Can control (vary) the resistance ex) dimmer switch |
What is a circuit breaker? | Saftey device that will open the circuit (break metal-to-metal contact) and turn off the electricity if there are too many volts or amps flowing into a house |
Name the brightest and dimmest: 1 battery, 4 lights in series; 1 battery, 5 lights in parallel: 1 battery, 3 lights in series | Brightest: 1 battery, 5 lights in parallel Dimmest: 1 battery, 4 lights in series |
A lightbulb is only 4% efficient in producing light. If 800J of input energy went into producing light, what is the output energy the bulb is capable of? | Efficiency=output/input x 100 Output= Input x Efficiency 32J |
Coal fired energy | Burning fossil fuels for energy -produces toxic fumes |
Hydroelectric | Using water currents to create electricity -disturbs natural water |
Nuclear | Splitting or combining atoms releasing bursts of energy -radioactive |
Solar | Uses suns energy to produce electricity -cannot collect on cloudy days |
Geothermal | Using heated steam from deep in the earth to produce electricity |
Input= 71J Output= 11J Efficiency=? | (Efficiency= output/input x 100) Efficiency = 15.5% |
Input= 100J Output= 34J | (Efficiency= output/input x 100) Efficiency = 34% |