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Questions and Answers
What is the current supplied by a nine volt battery to a cordless iron with a resistance of 18 Ω?
What is the current supplied by a nine volt battery to a cordless iron with a resistance of 18 Ω?
- 0.2 A
- 0.75 A
- 0.5 A (correct)
- 0.3 A
If a cd player has a resistance of 40 Ω and a current of 0.1 A flowing through it, what is the voltage across it?
If a cd player has a resistance of 40 Ω and a current of 0.1 A flowing through it, what is the voltage across it?
- 10 V (correct)
- 0.5 V
- 4 V
- 2 V
Which of the following statements about conventional current and electron flow is correct?
Which of the following statements about conventional current and electron flow is correct?
- Electron flow is the same as conventional current.
- Electron flow is based on the flow of protons.
- Conventional current actually refers to the movement of positive charges. (correct)
- Conventional current flows from negative to positive.
In a circuit with a 9V battery and a load of 18 Ω, what is the power consumed by the load?
In a circuit with a 9V battery and a load of 18 Ω, what is the power consumed by the load?
What is the total resistance in a circuit if three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in series?
What is the total resistance in a circuit if three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in series?
Flashcards
Conventional Current Flow
Conventional Current Flow
The conventional current flow is a model used to explain the direction of current flow. It states that the positive charges are moving from the positive terminal of the battery to the negative terminal. It's important to note that in actuality, the electrons are the ones moving, not the positive charges, but this model simplifies the concept for ease of understanding.
Electron Flow
Electron Flow
Electron flow is the actual flow of electrons within a circuit. The electrons, which carry negative charges, flow from the negative terminal of the battery to the positive terminal. It's important to understand that both conventional current and electron flow describe the same phenomenon, just from different perspectives.
Ohm's Law
Ohm's Law
Ohm's Law describes the relationship between voltage, current, and resistance in an electrical circuit. It states that the current flowing through a conductor is directly proportional to the voltage applied across its ends and inversely proportional to the conductor's resistance.
Voltage
Voltage
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Current
Current
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Study Notes
Disclaimer
- This presentation is for informational purposes only
- Examples, images, and references are for educational use only
- Credits for images are given to the original open source
- Images are not for promotional use
Conventional Current vs. Electron Flow
- Conventional Current: Charges flow from the positive terminal to the negative terminal
- Electron Flow: Charges flow from the negative terminal to the positive terminal
Electric Current (I)
- Electric current (I) is the flow of charges
- It is pushed by the voltage (V)
- It is opposed by the resistance (R)
Ohm's Law
- V = IR
- I = V/R
- R = V/I
Example Problem 1
- A nine-volt battery powers a cordless iron with a resistance of 18Ω
- The current is 0.5A (calculated using Ohm's Law)
Example Problem 2
- A CD player with a resistance of 40Ω has a current of 0.1A
- The voltage is 4V (calculated using Ohm's Law)
DC vs. AC
- DC (Direct Current):
- One pathway
- Constant voltage
- AC (Alternating Current):
- Periodic moving back and forth
- Changing voltage
Electric Circuit
- A closed loop of interconnected components
- Allows electric current to flow
Resistors in Series and Parallel Circuits
- Series Circuit: Resistors are connected end-to-end
- Parallel Circuit: Resistors are connected across each other
Series Circuit Example
- R1 = 15Ω, R2 = 2Ω, R3 = 3Ω
- Total resistance (Req) in series is calculated by adding the individual resistances
Series Circuit Example calculation:
- Req = R1 + R2 + R3 = 15Ω + 2Ω + 3Ω = 20Ω
- With a total voltage of 12V the resulting current (IT) using Ohm's law: IT = VT/Req = 12V/20Ω = 0.6A
Parallel Circuit Example
- R1 = 1Ω, R2 = 2Ω, R3 = 3Ω
- Total resistance (Req) in parallel is calculated using the reciprocal formula: 1/Req=1/ R1 + 1/R2 + 1/ R3
Parallel Circuit Example calculation:
- 1/Req = 1/1Ω + 1/2Ω + 1/3Ω = 11/6Ω
- Req = 6/11Ω
- With a total voltage of 12V the resulting current (IT) using Ohm's law: It = VT/Req = 12V/(6/11Ω) = 22A
Electric Power (P)
- P = V x I
- Units are Watts (W)
- where V = volts, I = current
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