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Questions and Answers
What is the relationship defined by Ohm's Law?
What is the relationship defined by Ohm's Law?
- Resistance is directly proportional to voltage.
- Voltage is independent of both current and resistance.
- Current is directly proportional to voltage and inversely proportional to resistance. (correct)
- Current is directly proportional to resistance.
If a light bulb has a resistance of 6 ohms and a current of 35 mA flows through it, what is the potential difference across the light bulb?
If a light bulb has a resistance of 6 ohms and a current of 35 mA flows through it, what is the potential difference across the light bulb?
- 0.15 V
- 0.21 V (correct)
- 0.50 V
- 0.30 V
What would be the current flowing through a device with a resistance of 44 ohms connected to a potential difference of 220 V?
What would be the current flowing through a device with a resistance of 44 ohms connected to a potential difference of 220 V?
- 4 A (correct)
- 2 A
- 5 A
- 10 A
For a copper wire with a resistance of 25 ohms connected with a potential difference of 50 V, what is the current flow through it?
For a copper wire with a resistance of 25 ohms connected with a potential difference of 50 V, what is the current flow through it?
A voltmeter reads 20 V across a resistance of 50 ohms. What is the current flowing through this resistance?
A voltmeter reads 20 V across a resistance of 50 ohms. What is the current flowing through this resistance?
What happens to the current flow in a circuit when resistance is increased?
What happens to the current flow in a circuit when resistance is increased?
Which instrument is used to measure electric current?
Which instrument is used to measure electric current?
If a current of 0.8 A flows for 4 minutes, how is the total charge calculated?
If a current of 0.8 A flows for 4 minutes, how is the total charge calculated?
What type of current always flows in one direction?
What type of current always flows in one direction?
How is potential difference measured between two points in a circuit?
How is potential difference measured between two points in a circuit?
What unit is used to measure electric resistance?
What unit is used to measure electric resistance?
When 3x105 coulombs pass through a wire in 2.5 seconds, what is the current flow?
When 3x105 coulombs pass through a wire in 2.5 seconds, what is the current flow?
Which of the following statements is true regarding the properties of electric current?
Which of the following statements is true regarding the properties of electric current?
How does the cross-sectional area of a conduction wire affect its resistance?
How does the cross-sectional area of a conduction wire affect its resistance?
If the length of a conduction wire is doubled, what happens to its resistance?
If the length of a conduction wire is doubled, what happens to its resistance?
In the formula $R = \frac{\rho l}{A}$, what does the symbol $\rho$ represent?
In the formula $R = \frac{\rho l}{A}$, what does the symbol $\rho$ represent?
When comparing two wires made of the same metal, how does a wire with a greater length affect its resistance?
When comparing two wires made of the same metal, how does a wire with a greater length affect its resistance?
If two metals have a resistivity ratio of 4:5 and equal lengths, how does their resistance compare?
If two metals have a resistivity ratio of 4:5 and equal lengths, how does their resistance compare?
What is the effect on resistance when the diameter of a wire is increased while keeping other factors constant?
What is the effect on resistance when the diameter of a wire is increased while keeping other factors constant?
If the resistivity of metal A is 8x10-8 Ωm and its length is 2m with a cross-sectional area of 0.05 cm2, what is its resistance?
If the resistivity of metal A is 8x10-8 Ωm and its length is 2m with a cross-sectional area of 0.05 cm2, what is its resistance?
Which statement correctly describes the relationship between resistance and cross-sectional area when both length and resistivity are constant?
Which statement correctly describes the relationship between resistance and cross-sectional area when both length and resistivity are constant?
Flashcards
Voltmeter Resistance
Voltmeter Resistance
A voltmeter must have very high resistance (ideally infinite) to accurately measure the voltage across a component without significantly affecting the circuit's current.
Ohm's Law
Ohm's Law
Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across its ends and inversely proportional to its resistance.
Calculate Current
Calculate Current
To find the current flowing through a component, divide the voltage across it by its resistance (I = V/R).
Calculate Voltage
Calculate Voltage
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Calculate Resistance
Calculate Resistance
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Electric Current
Electric Current
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Direct Current (DC)
Direct Current (DC)
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Alternative Current (AC)
Alternative Current (AC)
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Ammeter
Ammeter
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Resistance
Resistance
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Potential Difference
Potential Difference
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Voltmeter
Voltmeter
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Relationship between potential difference (V), current (I) and resistance (R)
Relationship between potential difference (V), current (I) and resistance (R)
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Resistance of a conduction wire
Resistance of a conduction wire
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Resistivity (ρ)
Resistivity (ρ)
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How does length affect resistance?
How does length affect resistance?
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How does cross-sectional area affect resistance?
How does cross-sectional area affect resistance?
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Formula for resistance
Formula for resistance
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Effect of stretching a wire on resistance
Effect of stretching a wire on resistance
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Comparing resistance of two wires
Comparing resistance of two wires
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Potential difference and resistance relationship
Potential difference and resistance relationship
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Study Notes
Electricity and Electrical Energy
- Electricity is a form of energy that can be transformed from other energy forms and vice versa.
- Current is defined as the flow of electric charge through a conductor, typically measured at a specific point in time. It represents how much electric charge flows past a given point in the circuit over the period of one second, impacting the circuit's overall performance.Electric
Electric Current Calculation
-
- Current (I) = Charge (Q) / Time (t)
- I is measured in Amperes (A), which indicates the flow rate of electric charge in a circuit. One ampere represents one coulomb of charge passing through a given point in one second.
- Q is measured in Coulombs (C), the unit of electric charge, where one coulomb is defined as the amount of electric charge that is moved by a constant current of one ampere over a duration of one second. This relationship helps to quantify not only the total charge in motion but also provides insight into the fundamental particle behavior of electrons as they traverse through a conductive medium, ultimately influencing how electrical energy is transmitted and utilized within various components of an electrical system.
- t is measured in seconds (s) and represents the duration over which the charge is flowing. This time factor is crucial for understanding how current behaves in electrical circuits.
- Current (I) = Charge (Q) / Time (t)
Practice Problems
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Problem 1: Calculate the current when a charge of 3 x 10-5 coulombs passes through a wire in 2.5 seconds.
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Answer: 1.2 x 10<sup>-5</sup> A -
Problem 2: Find the charge that passes through a wire with a current of 25 mA for 5 minutes.
- Answer: 75 coulombs
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Problem 3: A current of 0.8 A flows through a wire for 4 minutes. Determine the number of electrons passing through the wire.
- Answer: 1.92 x 10<sup>21</sup> electrons
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Problem 4: Calculate the charge flowing through a wire between 0 and 10 seconds based on the provided graph.
- Answer: 7.5 Coulombs
Ohm's Law
- Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.
- V = I x R (Voltage = Current x Resistance)
- V is measured in Volts (V)
- I is measured in Amperes (A)
- R is measured in Ohms (Ω)
Ohm's Law Practice Problems
-
Problem 1: A current of 35 mA flows through a light bulb with a resistance of 6 Ω. Calculate the potential difference across the bulb.
-
Answer: 0.21 V
-
Problem 2: An electric device with 44Ω resistance is connected with a 220V potential difference. Determine the current flowing through the device.
-
Answer: 5 A
-
Problem 3: A copper wire with 25Ω resistance is connected to a 50V potential difference. Calculate the current.
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Answer: 2 A
Additional Notes
- Types of Current: Direct Current (DC) flows in one direction, while Alternating Current (AC) flows in two directions.
- Resistance: Resistance is the property of an object that opposes the flow of current in a circuit. It's measured in Ohms (Ω).
- Potential Difference: The potential difference between two points is the energy lost by one coulomb of charge as it passes between the two points. It is measured in Volts (V)
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Description
Test your knowledge of electricity and electric current calculations with this quiz. You will solve problems involving charge, current, and the relationship between them, based on fundamental principles of electricity. Perfect for students learning about electricity in their physics classes.
