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Questions and Answers
In a series circuit, how does the current behave across all resistors?
In a series circuit, how does the current behave across all resistors?
- It remains the same across all resistors. (correct)
- It decreases proportionally to the resistance.
- It increases proportionally to the resistance.
- It fluctuates randomly.
In a series circuit, the source voltage is equally divided among all the resistors, regardless of their resistance values.
In a series circuit, the source voltage is equally divided among all the resistors, regardless of their resistance values.
False (B)
According to Ohm's Law, what happens to the voltage drop across a resistor in a series circuit if the resistance value increases?
According to Ohm's Law, what happens to the voltage drop across a resistor in a series circuit if the resistance value increases?
increases
In a series circuit containing multiple resistors, the equivalent resistance ($R_{eq}$) is the ______ of all individual resistances.
In a series circuit containing multiple resistors, the equivalent resistance ($R_{eq}$) is the ______ of all individual resistances.
What happens to the equivalent resistance in a series circuit if a new resistor is added?
What happens to the equivalent resistance in a series circuit if a new resistor is added?
If one resistor fails (opens) in a series circuit, current may continue to flow through the other resistors.
If one resistor fails (opens) in a series circuit, current may continue to flow through the other resistors.
What is the primary purpose of using series connections in a voltage divider circuit?
What is the primary purpose of using series connections in a voltage divider circuit?
A significant drawback of series circuits is that the more devices (resistors) are added, the less ______ passes through each device.
A significant drawback of series circuits is that the more devices (resistors) are added, the less ______ passes through each device.
Match the characteristics with the type of circuit that exhibits them:
Match the characteristics with the type of circuit that exhibits them:
Three resistors with values of 60.0 , 30.0 , and 20.0 are connected in parallel across a 90.0 V battery. What formula is needed to find the equivalent resistance?
Three resistors with values of 60.0 , 30.0 , and 20.0 are connected in parallel across a 90.0 V battery. What formula is needed to find the equivalent resistance?
In a parallel circuit with multiple resistors branched off, if one branch has significantly lower resistance than the others, it will draw more current through it than the other branches.
In a parallel circuit with multiple resistors branched off, if one branch has significantly lower resistance than the others, it will draw more current through it than the other branches.
In a parallel circuit, if the voltage source is 90V, what is the voltage across each of the resistors?
In a parallel circuit, if the voltage source is 90V, what is the voltage across each of the resistors?
If you have three parallel resistors,
$R_1$, $R_2$, and $R_3$, and you want to calculate the total current, you use the equation $I = \frac{\Delta V}{R}$. The $R$ represents the ______.
If you have three parallel resistors, $R_1$, $R_2$, and $R_3$, and you want to calculate the total current, you use the equation $I = \frac{\Delta V}{R}$. The $R$ represents the ______.
Consider a parallel-connected series with three resistors: 680 , 1.1 k, and 10.2 k. What is the correct setup to calculate the equivalent resistance?
Consider a parallel-connected series with three resistors: 680 , 1.1 k, and 10.2 k. What is the correct setup to calculate the equivalent resistance?
In a parallel circuit, all components must have the exact same resistance value for the circuit to function correctly.
In a parallel circuit, all components must have the exact same resistance value for the circuit to function correctly.
When can you use a voltage divider circuit?
When can you use a voltage divider circuit?
A voltage divider produces a potential difference that is ______ than the potential difference across the battery.
A voltage divider produces a potential difference that is ______ than the potential difference across the battery.
In a voltage divider with two resistors (390 and 470 ) in series connected to a 9.0 V battery, what is the known variables in the circuit?
In a voltage divider with two resistors (390 and 470 ) in series connected to a 9.0 V battery, what is the known variables in the circuit?
The purpose of a voltage divider is to equally divide the voltage regardless of the resistor's value.
The purpose of a voltage divider is to equally divide the voltage regardless of the resistor's value.
In a voltage divider circuit, what happens to the circuit when the resistance is increased
In a voltage divider circuit, what happens to the circuit when the resistance is increased
In electric circuits, a ______ acts as a safety device by melting and stopping the current when it becomes too large.
In electric circuits, a ______ acts as a safety device by melting and stopping the current when it becomes too large.
What triggers a circuit breaker to interrupt the flow of current in an electrical circuit?
What triggers a circuit breaker to interrupt the flow of current in an electrical circuit?
A ground-fault interrupter (GFI) primarily protects electrical circuits from voltage spikes and surges.
A ground-fault interrupter (GFI) primarily protects electrical circuits from voltage spikes and surges.
What is the working principle of a Ground-Fault Interrupter (GFI)?
What is the working principle of a Ground-Fault Interrupter (GFI)?
In a combined series-parallel circuit, some components are connected in series while others are connected in ______.
In a combined series-parallel circuit, some components are connected in series while others are connected in ______.
Match the circuit component with its function
Match the circuit component with its function
Which of the following best describes a combined series-parallel circuit?
Which of the following best describes a combined series-parallel circuit?
In a combined series-parallel circuit, the total current must flow through all components.
In a combined series-parallel circuit, the total current must flow through all components.
How are current and voltage related in a series circuit?
How are current and voltage related in a series circuit?
In circuits a ______ is used to measure voltage drop.
In circuits a ______ is used to measure voltage drop.
What is a key difference in how ammeters and voltmeters are connected in a circuit?
What is a key difference in how ammeters and voltmeters are connected in a circuit?
An ideal ammeter should have very high resistance to minimize its impact on the circuit's current.
An ideal ammeter should have very high resistance to minimize its impact on the circuit's current.
What should the resistance be for a voltmeter?
What should the resistance be for a voltmeter?
The strength of a permanent magnet remains consistent unless exposed to very high temperatures or ______.
The strength of a permanent magnet remains consistent unless exposed to very high temperatures or ______.
Match the magnetic property with its description:
Match the magnetic property with its description:
What happens to the magnetic domains inside a ferromagnetic material when it becomes magnetized?
What happens to the magnetic domains inside a ferromagnetic material when it becomes magnetized?
A magnetic domain is a single atom within a ferromagnetic material that acts as an individual magnet.
A magnetic domain is a single atom within a ferromagnetic material that acts as an individual magnet.
What does field lines represent in a magnetic field?
What does field lines represent in a magnetic field?
Magnetic flux per unit area is proportional to the strength of the ______ field.
Magnetic flux per unit area is proportional to the strength of the ______ field.
What is the shape of magnetic field around a long straght current-carrying wire?
What is the shape of magnetic field around a long straght current-carrying wire?
The magnetic field strength around a current-carrying wire decreases with the wire's temperatrure decrease.
The magnetic field strength around a current-carrying wire decreases with the wire's temperatrure decrease.
Flashcards
Series Connection
Series Connection
Components connected with one current path
Series Circuit Current
Series Circuit Current
The current throughout all resistors is the same
Series Circuit Voltage
Series Circuit Voltage
The source Voltage is shared across the resistors
Equivalent Resistance in Series
Equivalent Resistance in Series
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Equivalent Resistor in Parallel
Equivalent Resistor in Parallel
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Voltage in Parallel Circuit
Voltage in Parallel Circuit
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Current in Parallel Circuit
Current in Parallel Circuit
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Voltage Divider
Voltage Divider
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Fuse
Fuse
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Circuit Breaker
Circuit Breaker
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Ground Fault Interrupter (GFI)
Ground Fault Interrupter (GFI)
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Combined Series-Parallel Circuit
Combined Series-Parallel Circuit
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Voltmeter
Voltmeter
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Ammeter
Ammeter
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Properties of Magnets
Properties of Magnets
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Magnetic Domains
Magnetic Domains
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Magnetic Flux
Magnetic Flux
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Solenoid
Solenoid
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Electromagnet
Electromagnet
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Kirchhoff's Loop Rule
Kirchhoff's Loop Rule
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Kirchhoff's Junction Rule
Kirchhoff's Junction Rule
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Study Notes
- These study notes are for revision of End of Term 2 physics, covering series and parallel circuits, Kirchhoff's rules, electromagnetism, and forces on charged particles/wires in magnetic fields.
Series Circuits
- Series circuits involve components connected along a single path, meaning current has only one route to flow.
- The current is consistent throughout all resistors in a series circuit (I = I₁ = I₂ = etc.).
- The source voltage is divided (shared) among the resistors (V = V₁ + V₂ + etc.).
- The equivalent resistance (Req) is the sum of individual resistances (Req = R₁ + R₂ + R₃ + etc.).
- If all resistors have the same resistance, then: Req = nR.
- A larger equivalent resistance exists than the largest resistance in the circuit.
- Adding a new resistor increases Req and decreases the current.
- You can find the source current from the equivalent circuit using Ohm's Law.
- If one resistor breaks, the circuit opens, and current flow ceases.
- Series connections function as voltage divider circuits, reducing the voltage to operate loads requiring lower voltage.
- A problem with series circuits is that adding more resistors decreases current (dimming bulbs).
- If one resistor breaks (bulb goes out), the entire series turns off.
Parallel Circuits
- Equivalent Resistance (Req ) and Current in Parallel Circuits In a parallel circuit, resistors are connected across the power source, allowing multiple paths for current to flow.
Series-Parallel Circuits
- This configuration combines both series and parallel connections. Some components are in series, so current flows sequentially through them. Other components exist in parallel, allowing current to split and flow through multiple paths.
Problem Solving
- You can use the equation I = ΔV/R to find the current through each branch.
- Solving for Req involves using the reciprocal sum of resistance formula.
- Total current is found by dividing total voltage by equivalent resistance (I = ΔV/ Req)
Resistors
- The resistor with the smallest resistance will be the hottest.
- The resistor with the largest resistance will be the coolest.
Voltage Dividers
- The voltage divider produces a source of voltage that is less then the potential difference in the battery
Kirchhoff's Rules
- Kirchhoff's Loop Rule: indicates that the sum of increases in electric potential around a closed loop equals the sum of decreases in electric potential around the same loop.
- Kirchhoff's Junction Rule: states that the total current entering a junction must equal the total current leaving that junction.
Circuit Protection
- Fuses: short pieces of metal that melt and break the circuit if the current is too high.
- Circuit Breakers: automatic switches that stop current flow when it exceeds a threshold. They often use a bimetallic strip that bends and releases a latch when overheated.
- Ground-Fault Interrupters (GFIs): devices that detect small differences in current between the two wires connected to an appliance. It interrupts the current, protecting against electrocution.
Measuring circuits
- Voltmeters A device used to measure the voltage drop through any part of circuit, it is connected in parallel with the circuit, it has a big resistance.
- Ammeters A device used to measure the current through any part of circuit, it connected in series with circuit and it has a small resistance.
Magnetism
- Magnets attract ferromagnetic substances.
- Like poles repel, while unlike poles attract.
- A suspended magnet aligns in a north-south direction.
- Magnetic poles always occur in pairs.
- You can visualize magnetic fields using magnetic field lines.
- Flux per unit area is proportional to magnetic field strength
Terms
- Magnetic domains: give a permanent or temporary magnet its properties
- Magnetic flux: is defined as the number of magnetic field lines passing through a given closed surface.
- Electromagnet: a magnet whose magnetic field is produced by electric current.
Magnetic Fields from Current-Carrying Wires
- The magnetic field around a current-carrying wire is perpendicular to the wire.
- The field forms closed loops with strength proportional to the current and inversely proportional to the distance from the wire.
- Apply the right-hand rule to determine direction: point thumb in the direction of current and fingers encircle the wire in the direction of the magnetic lines.
- A wire coiled into many loops is a solenoid. Each loop produces its own magnetic field, and inside the solenoid, the fields are all in the same direction and add together.
Electromagnets
- Solenoids that become electromagnets that produce magnetic fields much stronger than permanent magnets
- Electromagnet strength is proportional to current and loops in the solenoid
- Can be increased by placing an iron rod inside the solenoid
Forces on Charged Particles/Wires in Magnetic Fields
- Applies the right-hand rule to find the direction of the force on a current-carrying wire or charged particle placed in an external magnetic field.
- The force on a charged particle is calculated by F = qvBsin(θ), where q is charge, v is velocity, B is the magnetic field strength, and θ is the angle between v and B.
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