Resistors | Electricity | Physics | FuseSchool

Summary

This educational video explores the concept of electrical resistance and its role in circuits. It explains how electric current flows through conductors, causing collisions between electrons and atoms, which generates heat. Voltage propels electrons, with Ohm's Law (V=IR) defining the relationship between voltage, current, and resistance. The video demonstrates calculating resistance with examples and highlights that resistance increases with temperature due to increased atomic vibrations, affecting electron flow.

Takeaways

• 🔌 Electrical resistance is the ability of a material to resist the flow of electric current.
• 🚀 The flow of electric charge is known as electric current, measured in amperes (amps).
• 🌐 Conductors are made of atoms in a metallic lattice that allows free electrons to move, creating current.
• 💥 Electrons colliding with atoms in a conductor transfer energy, often resulting in heat.
• 🔋 Voltage, measured in volts, is the electrical potential difference needed to push electrons through a conductor.
• ⚖️ Ohm's Law (V = IR) relates voltage, current, and resistance in an electrical circuit.
• 📏 Resistance is measured in ohms and symbolized by the Greek letter omega (Ω).
• 🔄 To double the current in a wire, double the voltage applied according to Ohm's Law.
• 🔄 The formula for Ohm's Law can also be rearranged to find current (I = V/R) or resistance (R = V/I).
• 🔍 The resistance of a conductor increases with temperature due to increased atomic vibrations.
• 💡 An example of this is an incandescent light bulb, where the filament's resistance increases as it gets hotter.

Q & A

What is the definition of an electric current?

An electric current is the flow of electric charge, composed of negative electrons, through a conductor. It is measured in coulombs per second, also known as amps or amperes.

What causes the electrons to collide as they flow through a conductor?

As the current flows through the conductor, the electrons collide with the atoms in the metallic lattice, transferring energy, which can manifest as heat.

What is the unit of measurement for electric current?

The unit of measurement for electric current is the ampere, also known as amps.

What is the role of voltage in an electrical circuit?

Voltage, measured in volts, is the difference in electrical potential that propels electrons through the metallic structure of a conductor.

How is the amount of energy per coulomb measured in an electrical circuit?

The amount of energy per coulomb is measured in joules per coulomb, which is the definition of voltage.

What does the term 'resistance' in an electrical circuit refer to?

Resistance in an electrical circuit refers to the opposition to the flow of electric current, which is caused by the collisions of electrons with atoms in the conductor.

Who discovered the relationship between voltage, current, and resistance in a circuit?

George Ohm discovered the relationship, which is known as Ohm's Law.

What is Ohm's Law and how is it represented mathematically?

Ohm's Law states the relationship between voltage (V), current (I), and resistance (R) in a circuit, represented mathematically as V = I × R.

How can you calculate the resistance of a wire given its current and voltage?

You can calculate the resistance of a wire using the formula R = V / I, where R is resistance in ohms, V is voltage in volts, and I is current in amps.

What is the symbol used to represent resistance in ohms?

The symbol used to represent resistance in ohms is the Greek letter omega (Ω).

How does the temperature of a conductor affect its resistance?

The resistance of a conductor increases with temperature because the increased vibration of atoms leads to more frequent collisions with electrons, making it harder for the electrons to flow.

Can you provide an example of how resistance changes with temperature in a real-world scenario?

An example is an old-fashioned filament bulb, where the resistance of the filament increases as it gets hotter due to increased atomic vibrations.

Outlines

00:00

🔌 Understanding Electrical Resistance

This paragraph introduces the concept of electrical resistance, explaining the role of resistors in an electrical circuit. It describes how an electric current flows through a conductor, which is made of atoms joined in a metallic lattice. The electrons in the current collide with these atoms, transferring energy and causing the conductor to heat up. The paragraph also explains the necessity of a voltage difference to drive the electrons and how different conductors exhibit varying resistances. Ohm's Law is introduced as the relationship between voltage (V), current (I), and resistance (R), formulating it as V = I * R. An example is provided to illustrate how to calculate resistance using this law.

📐 Ohm's Law and Resistance Calculation

This section delves deeper into Ohm's Law, demonstrating how it can be represented in a formula triangle to show the relationships between voltage, current, and resistance. It provides an example calculation where the resistance of a wire is determined using the given current and voltage. The paragraph challenges viewers to pause the video and solve for the resistance of a lamp in a circuit, offering a practical application of Ohm's Law. Additionally, it introduces the concept that the resistance of a conductor increases with temperature due to increased atomic vibrations, which in turn causes more frequent electron collisions and higher resistance, exemplified by the behavior of a filament bulb as it heats up.

Keywords

💡Electrical Resistance

Electrical resistance is the opposition to the flow of electric current in a conductor. It is a fundamental concept in the script, as it explains how materials can impede the movement of electrons, which is essential for understanding how circuits operate. The script mentions that different conductors have different resistances due to their metallic structures, which is a key factor in how a circuit behaves.

💡Resistor

A resistor is a component in an electrical circuit that is specifically designed to have a certain amount of resistance. It is used to control the flow of current in a circuit, as explained in the script. Resistors are crucial in various applications, such as setting the current levels in electronic devices or dividing voltages.

💡Electric Current

Electric current is the flow of electric charge, typically carried by moving electrons through a conductor. In the script, it is described as being measured in coulombs per second, also known as amps or amperes. The concept of current is central to the video's theme, as it is the flow that resistors are designed to resist.

💡Conductor

A conductor is a material that allows the flow of electric current. In the script, it is explained that conductors are made of atoms joined in a metallic lattice with free electrons. The resistance of a conductor is influenced by its atomic structure and the resulting electron collisions.

💡Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering that relates voltage, current, and resistance in a circuit. The script presents Ohm's Law as the formula V = I * R, where V is voltage, I is current, and R is resistance. This law is central to the video's educational content, as it provides a mathematical basis for understanding how these quantities interact.

💡Voltage

Voltage, measured in volts, is the electrical potential difference between two points in a circuit. The script describes it as the force that propels electrons through a conductor. Voltage is a key component in Ohm's Law and is essential for understanding how much energy is needed to drive the current through a resistor.

💡Current Measurement

The measurement of electric current is mentioned in the script as being in coulombs per second, or amps (amperes). This measurement is crucial for understanding the rate of flow of electric charge in a circuit, which is directly related to the concept of resistance.

💡Energy Transfer

Energy transfer in the context of the script refers to the process where energy is moved from one form to another, such as from electrical energy to heat, as electrons collide with atoms in a conductor. This concept is used to explain why a wire carrying current can feel warm.

💡Temperature Effect on Resistance

The script explains that the resistance of a conductor increases with temperature due to increased atomic vibrations, which leads to more frequent collisions with electrons. This is exemplified by the filament in an old-fashioned bulb, which gets hotter and thus has increasing resistance as current flows through it.

💡Calculation Examples

The script provides examples of how to calculate resistance, voltage, and current using Ohm's Law. These examples serve as practical applications of the theoretical concepts discussed in the video, helping viewers understand how to apply Ohm's Law in real-world scenarios.

💡Ohm

The ohm is the unit of electrical resistance. In the script, it is mentioned as the unit for measuring resistance (R) in Ohm's Law. The symbol for ohm is omega (Ω), and it is used to quantify the opposition to current flow in a circuit.

Highlights

Electrical resistance is the ability of a material to withstand the flow of electric current.

Electric current is the flow of electric charge, measured in coulombs per second or amps.

Conductors are made of atoms joined in a metallic lattice structure with free electrons.

Electrons collide with atoms in the conductor, transferring energy and causing the wire to feel warm.

Voltage is the electrical potential difference, measured in volts, needed to propel electrons.

Different conductors have different metallic structures, resulting in varying resistances.

High resistance components require a higher voltage to move electrons through them.

Ohm's Law (V=IR) relates voltage, current, and resistance in an electrical circuit.

Resistance is measured in ohms, symbolized by the Greek letter omega (Ω).

To double the current in a wire, double the applied voltage, according to Ohm's Law.

Example calculation: Resistance of a wire with 5 amps current and 80 volts potential difference is 16 ohms.

The resistance of a conductor increases with temperature due to increased atomic vibrations.

As temperature rises, electrons collide more often with atoms, increasing resistance.

The resistance of an incandescent filament bulb increases as the filament heats up.

Understanding resistance is crucial for calculating and designing electrical circuits.

Ohm's Law provides a fundamental relationship for electrical engineering and circuit analysis.

Practical applications of resistance include controlling current flow and managing heat generation in circuits.

Transcripts

have you ever heard the expression

resisting temptation

resisting means to withstand something

and that's what electrical resistors and

resistance in an electrical circuit does

in this video we're going to learn about

electrical resistance and resistors

an electric current is the flow of

electric charge composed of negative

electrons through a conductor

it is measured in coulombs per second

also known as amps or amperes

the conductor is made of atoms joined in

a metallic lattice of free electrons

as the current flows through the

conductor the electrons collide with the

atoms

energy is thus transferred

for example to heat

this explains why a wire with

electricity flowing through it often

feels warm to the touch

a difference in electrical potential

measured in volts is needed to propel

the electrons through the metallic

structure

the voltage measures the amount of

energy per coulomb or joules per coulomb

different conductors will have different

metallic structures

and so exhibit different resistances in

a circuit

a component with a high resistance will

need a higher potential difference or

voltage to move electrons through it

compared to one of a lower resistance

george ohm found a relationship between

voltage current and resistance in a

circuit

which we know as ohm's law

v equals i times r

r is the resistance measured in ohms

v is voltage measured in volts

and i is current measured in amps

thus for a particular wire if you want

to double the current flowing you need

to double the voltage applied

ohm's law can be displayed in a formula

triangle like this

voltage equals current multiplied by

resistance

current equals voltage divided by

resistance

and resistance equals voltage divided by

current

let's try an example

a wire is carrying a current of 5 amps

with a potential difference of 80 volts

across it

what's the resistance of the wire

pause the video for a moment and have a

go

[Music]

we should use the equation r equals v

over i

which equals 80 volts over 5 amps

which equals 16 ohms

remember resistance is measured in ohms

and the symbol for this is

omega

let's try two more examples calculate

the resistance of the lamp in this

circuit pause the video while you work

out the answers

[Music]

calculate the voltage or potential

difference across the

lamp did you get them right

you also need to know that the

resistance of a conductor increases as

its temperature increases

this is because temperature is a measure

of the vibration of the atoms within the

conductor

as the atoms vibrate more

so the electrons collide more often

making it more difficult for the

electrons to flow and so increasing the

resistance

thus the resistance of an old-fashioned

filament bulb increases as the filament

gets hotter and hotter

so that's how resistance happens in a

circuit and how it can be calculated