Resistors | Electricity | Physics | FuseSchool
Summary
TLDRThis 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
🔌 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.
Mindmap
Keywords
💡Electrical Resistance
💡Resistor
💡Electric Current
💡Conductor
💡Ohm's Law
💡Voltage
💡Current Measurement
💡Energy Transfer
💡Temperature Effect on Resistance
💡Calculation Examples
💡Ohm
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
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