Podcast
Questions and Answers
A wire's resistance is found to increase when both its length and temperature increase. How does this affect the wire's resistivity?
A wire's resistance is found to increase when both its length and temperature increase. How does this affect the wire's resistivity?
- Resistivity remains constant.
- Resistivity increases. (correct)
- Resistivity decreases.
- The effect on resistivity cannot be determined.
A circuit contains a thermistor. What happens to the current in the circuit if the temperature increases, assuming the voltage remains constant?
A circuit contains a thermistor. What happens to the current in the circuit if the temperature increases, assuming the voltage remains constant?
- The current decreases.
- The current increases. (correct)
- The current remains constant.
- The current fluctuates erratically.
A light-dependent resistor (LDR) is used in a circuit. How does increasing light intensity affect the power dissipated by the LDR, assuming the voltage across it remains constant?
A light-dependent resistor (LDR) is used in a circuit. How does increasing light intensity affect the power dissipated by the LDR, assuming the voltage across it remains constant?
- Power fluctuates unpredictably.
- Power remains the same.
- Power decreases. (correct)
- Power increases.
Which of the following scenarios would result in a component being classified as a 'non-Ohmic device'?
Which of the following scenarios would result in a component being classified as a 'non-Ohmic device'?
A battery with a constant EMF is connected to a circuit. If the total charge moved from one terminal to another increases, what happens to the work done by the battery?
A battery with a constant EMF is connected to a circuit. If the total charge moved from one terminal to another increases, what happens to the work done by the battery?
A circuit contains a 9V battery with an internal resistance of 0.5 ohms connected to a 4 ohm external resistor. What is the terminal potential difference across the battery?
A circuit contains a 9V battery with an internal resistance of 0.5 ohms connected to a 4 ohm external resistor. What is the terminal potential difference across the battery?
What is the primary purpose of a potential divider circuit?
What is the primary purpose of a potential divider circuit?
If three resistors with resistances of 2 ohms, 4 ohms, and 6 ohms are connected in parallel, what is the equivalent resistance of the combination?
If three resistors with resistances of 2 ohms, 4 ohms, and 6 ohms are connected in parallel, what is the equivalent resistance of the combination?
In a circuit with two resistors in series, $R_1$ and $R_2$, if the voltage across $R_1$ is 4V and the voltage across $R_2$ is 8V, and the current through $R_1$ is 2A, what is the resistance of $R_2$?
In a circuit with two resistors in series, $R_1$ and $R_2$, if the voltage across $R_1$ is 4V and the voltage across $R_2$ is 8V, and the current through $R_1$ is 2A, what is the resistance of $R_2$?
An ideal ammeter and an ideal voltmeter are placed in a circuit to measure the current through a resistor and the voltage across it, respectively. How should these meters be connected in the circuit to obtain accurate measurements?
An ideal ammeter and an ideal voltmeter are placed in a circuit to measure the current through a resistor and the voltage across it, respectively. How should these meters be connected in the circuit to obtain accurate measurements?
Flashcards
Potential Difference
Potential Difference
The work done per unit charge to move a charge.
Electric Current
Electric Current
The rate of flow of charge through a conductor.
Electric Resistance
Electric Resistance
Potential difference across a conductor divided by current.
Ohm's Law
Ohm's Law
Signup and view all the flashcards
Electromotive Force (EMF)
Electromotive Force (EMF)
Signup and view all the flashcards
Direction of Electron Flow
Direction of Electron Flow
Signup and view all the flashcards
Current in Series Circuit
Current in Series Circuit
Signup and view all the flashcards
Current in Parallel Circuit
Current in Parallel Circuit
Signup and view all the flashcards
Terminal Potential Difference
Terminal Potential Difference
Signup and view all the flashcards
Potential Divider
Potential Divider
Signup and view all the flashcards
Study Notes
Current and Circuits
- Potential Difference (V): Work done per unit charge to move a charge from one point to another. Unit: volts (V).
- Electric Current (I): Rate of flow of charge. Unit: amperes (A). Defined as the flow of 1 coulomb of charge per second.
- Electric Resistance (R): Potential difference across a component divided by the current through it. Unit: ohms (Ω).
- Ohm's Law: At a constant temperature, current through a conductor is directly proportional to the potential difference across it. (I ∝ V)
- Factors Affecting Resistance:
- Nature of the material: Materials with many free electrons have lower resistance.
- Length of the conductor: Longer conductors have higher resistance.
- Cross-sectional area of the conductor: Larger areas result in lower resistance.
- Temperature: Increasing temperature usually increases resistance in conductors.
Voltage, Power, and EMF
- Voltage: Potential difference across a conductor.
- Electric Power (P): Energy per unit time dissipated in a conductor or rate of doing work. Unit: watts (W). Calculated as P = IV.
- Electromotive Force (EMF, E): Work done per unit charge in moving charge from one terminal of a battery to the other. Unit: volts (V).
Resistors in Electric Circuits
- Resistor Symbols: Various resistor symbols are used in circuit diagrams.
- Resistors in Series: Total resistance is the sum of individual resistances (RT = R1 + R2 + ...). Current is same throughout.
- Resistors in Parallel: Reciprocal of total resistance is the sum of the reciprocals of individual resistances (1/RT = 1/R1 + 1/R2 + ...). Voltage is same across each resistor.
Terminal Potential Difference and Potential Divider
- Terminal Potential Difference: Voltage across a component when current flows through it. Less than the EMF when there is internal resistance.
- Internal Resistance (r): Resistance within the cell/battery itself due to the chemical reactions; affects terminal potential difference. V=E-Ir
- Potential Divider: A circuit with multiple resistors used to tap off certain voltages based on resistances and source voltage. Allows various voltage outputs less than the source voltage.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
