Podcast
Questions and Answers
An electric current exists only when electric charges of like signs move.
An electric current exists only when electric charges of like signs move.
False
The SI unit of current is Coulomb (C).
The SI unit of current is Coulomb (C).
False
In a common conductor like copper, the current is due to the motion of positively charged electrons.
In a common conductor like copper, the current is due to the motion of positively charged electrons.
False
The average current is defined as the charge passing through an area per unit area.
The average current is defined as the charge passing through an area per unit area.
Signup and view all the answers
The drift speed of charge carriers in a conductor is directly proportional to the current density.
The drift speed of charge carriers in a conductor is directly proportional to the current density.
Signup and view all the answers
A mobile charge carrier in a metal can be either positive or negative.
A mobile charge carrier in a metal can be either positive or negative.
Signup and view all the answers
The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.
The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.
Signup and view all the answers
The potential difference across a conductor with uniform field is related to the field through the relationship J = I/A.
The potential difference across a conductor with uniform field is related to the field through the relationship J = I/A.
Signup and view all the answers
The units of resistance are expressed in ohms (Ω).
The units of resistance are expressed in ohms (Ω).
Signup and view all the answers
The resistance of a material increases as its temperature decreases.
The resistance of a material increases as its temperature decreases.
Signup and view all the answers
The circuit resistance decreases when resistors R1 and R2 are in parallel and the switch is closed, resulting in an increase in current.
The circuit resistance decreases when resistors R1 and R2 are in parallel and the switch is closed, resulting in an increase in current.
Signup and view all the answers
An ammeter measures voltage and should be connected in parallel.
An ammeter measures voltage and should be connected in parallel.
Signup and view all the answers
The equivalent capacitance of capacitors connected in parallel is the inverse of the equivalent capacitance of capacitors connected in series.
The equivalent capacitance of capacitors connected in parallel is the inverse of the equivalent capacitance of capacitors connected in series.
Signup and view all the answers
If the material obeys Ohm’s law, the energy equivalent of one kilowatt-hour can be calculated using the formula E = P*t.
If the material obeys Ohm’s law, the energy equivalent of one kilowatt-hour can be calculated using the formula E = P*t.
Signup and view all the answers
The potential difference across a conductor with a uniform field is related to the field through the relationship J = I/A.
The potential difference across a conductor with a uniform field is related to the field through the relationship J = I/A.
Signup and view all the answers
In a series circuit, the potential differences across the resistors add directly to give the equivalent resistance of the series combination.
In a series circuit, the potential differences across the resistors add directly to give the equivalent resistance of the series combination.
Signup and view all the answers
The equivalent resistance of a series combination of resistors is the algebraic sum of the individual resistances and is always less than any of the individual resistors.
The equivalent resistance of a series combination of resistors is the algebraic sum of the individual resistances and is always less than any of the individual resistors.
Signup and view all the answers
Replacing any resistors in series or in parallel reduces a complicated circuit to a simple circuit with only one resistor.
Replacing any resistors in series or in parallel reduces a complicated circuit to a simple circuit with only one resistor.
Signup and view all the answers
In a parallel circuit, the inverse of the equivalent resistance of two or more resistors connected in parallel is the algebraic sum of the inverses of the individual resistances, and the equivalent is always greater than the smallest resistor in the group.
In a parallel circuit, the inverse of the equivalent resistance of two or more resistors connected in parallel is the algebraic sum of the inverses of the individual resistances, and the equivalent is always greater than the smallest resistor in the group.
Signup and view all the answers
When resistors are connected in parallel, the potential difference across each resistor is not the same because each is connected directly across the battery terminals.
When resistors are connected in parallel, the potential difference across each resistor is not the same because each is connected directly across the battery terminals.
Signup and view all the answers
Study Notes
Electric Current
- Electric current exists only when electric charges of like signs move.
- The SI unit of current is not Coulomb (C), but rather Ampere (A).
Conduction
- In a common conductor like copper, the current is due to the motion of positively charged electrons.
- The average current is defined as the charge passing through an area per unit area.
- The drift speed of charge carriers in a conductor is directly proportional to the current density.
Resistance
- The resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area.
- The units of resistance are expressed in ohms (Ω).
- The resistance of a material increases as its temperature decreases.
Circuit Analysis
- When resistors R1 and R2 are in parallel and the switch is closed, the circuit resistance decreases, resulting in an increase in current.
- An ammeter measures current, not voltage, and should be connected in series.
- The equivalent capacitance of capacitors connected in parallel is the inverse of the equivalent capacitance of capacitors connected in series.
Ohm's Law
- If the material obeys Ohm's law, the energy equivalent of one kilowatt-hour can be calculated using the formula E = P*t.
Series and Parallel Circuits
- In a series circuit, the potential differences across the resistors add directly to give the equivalent resistance of the series combination.
- The equivalent resistance of a series combination of resistors is the algebraic sum of the individual resistances and is always greater than any of the individual resistors.
- Replacing any resistors in series or in parallel reduces a complicated circuit to a simple circuit with only one resistor.
- In a parallel circuit, the inverse of the equivalent resistance of two or more resistors connected in parallel is the algebraic sum of the inverses of the individual resistances, and the equivalent is always less than the smallest resistor in the group.
- When resistors are connected in parallel, the potential difference across each resistor is the same because each is connected directly across the battery terminals.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on electric current, current density, conductivity, resistivity, Ohm's Law, electrical energy, and power. Understand the concept of electric charges moving to create an electric current and the calculation of current using the SI unit Ampere (A).
