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.
Studying That Suits You
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Description
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.
