Questions and Answers
What is Ohm's Law formula wheel?
What does P stand for?
Power
What is the unit of measure for power?
Watts (W)
What does I stand for?
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What is the unit of measure for current?
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What does V stand for?
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What is the unit of measure for electro-motive force?
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What does R stand for?
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What is the unit of measure for resistance?
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What does the square root symbol (√) signify?
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What does the symbol ² represent?
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V x I = P translate to units of measure
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R x I² = P translate to units of measure
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V² / R = P translate to units of measure
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R x I = V translate to units of measure
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P / I = V translate to units of measure
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√(P x R) = V translate to units of measure
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V / I = R translate to units of measure
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V² / P = R translate to units of measure
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P / I² = R translate to units of measure
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V / R = I translate to units of measure
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P / V = I translate to units of measure
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√(P / R) = I translate to units of measure
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If we connect a 12-volt battery to a lamp, measure the current, and find that it draws 1 amp, how much power is being consumed?
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If we have a circuit with a 12-volt battery, a lamp, and a resistor connected in series, how much current would flow if the total resistance in the circuit is 150 ohms?
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What is the resistance of a cable that allows 10 amps to flow through it when it is connected to a 24-volt battery?
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A 2 amp fuse and a 100 ohm resistor are wired in series. What is the minimum voltage required to blow the fuse?
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A lamp is rated at 500 watts at 12 volts. What is the effective resistance of the filament at its operating temperature?
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Shop electric needs to run DC power to a 16 amp LED panel 50' away. How much power is converted to heat if the current is 16 amps?
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In a 24 volt circuit, a lamp draws 6.25 amps. What is the effective resistance of the lamp?
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If a current of 1 amp is flowing through a 150-ohm resistor in a DC circuit, what is the voltage drop across the resistor?
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A 12-volt circuit has a 3 amp fuse. How much resistance is needed in the circuit to keep the fuse from blowing?
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How many ohms are there in a megaohm?
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How many ohms are there in a milliohm?
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The prefix milli means what?
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The prefix mega means what?
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The prefix kilo means what?
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How many watts are in a kilowatt?
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How many watts are in a milliwatt?
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How many volts are in a kilovolt?
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How many volts are in a millivolt?
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What is Power Formula wheel?
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What is Ohm's Law wheel?
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Study Notes
Ohm's Law Formula Wheel
- Ohm's Law establishes the relationship between voltage (V), current (I), resistance (R), and power (P) in electrical circuits.
- The formulas derived from Ohm's Law can be manipulated to find any one of the four variables when the other three are known.
Power and Current
- Power (P) is measured in watts (W) and indicates how much energy is consumed or produced.
- Current (I) is the flow of electric charge, measured in amps (A).
Voltage and Resistance
- Electro-motive force (voltage) is the potential difference that drives current through a circuit, measured in volts (V).
- Resistance (R) opposes the flow of current, measured in ohms (Ω).
Key Formulas
- P = V x I translates to watts = volts x amps.
- R = V / I translates to ohms = volts / amps.
- P = I² x R translates to watts = amps² x ohms.
- V = I x R translates to volts = amps x ohms.
- V = P / I translates to volts = watts / amps.
Square Root Formulas
- V = √(P x R) translates to volts = square root of (watts x ohms).
- I = √(P / R) translates to amps = square root of (watts / ohms).
Practical Examples
- A 12-volt battery supplying a lamp that draws 1 amp consumes 12 watts of power.
- In a series circuit with a 12-volt battery and a total resistance of 150 ohms, the current is 0.08 amps.
- If a 24-volt battery provides power to a device with a resistance of 2.4 ohms, it allows for 10 amps of current.
Resistance and Fuse Ratings
- A circuit with a 2 amp fuse and a 100 ohm resistor requires a minimum voltage of 200 volts to blow the fuse.
- A lamp rated at 500 watts at 12 volts has an effective resistance of 0.288 ohms.
Heat in Conductors
- A 16 amp current through a 20 gauge wire with 10 ohms of resistance over distances yields 256 watts converted to heat.
Conversion Factors
- 1 megaohm = 1,000,000 ohms.
- 1 milliohm = 0.01 ohms.
- The prefix "milli" signifies one thousandth (0.001).
- The prefix "mega" signifies one million (1,000,000).
- The prefix "kilo" signifies one thousand (1,000).
- There are 1,000 watts in a kilowatt and 0.001 watts in a milliwatt.
- A kilovolt is equal to 1,000 volts, while a millivolt is equal to 0.001 volts.
Conclusion
- Familiarity with these concepts allows for effective analysis and troubleshooting of electrical systems. Understanding Ohm's Law is essential for anyone working in electrical engineering or related fields.
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Test your knowledge of Ohm's Law with these flashcards. Each card challenges you on key concepts such as power, current, and electro-motive force. Perfect for reinforcing fundamental physics principles.