Lesson 2: How Electricity is Generated? Flashcards

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1
Q

How does an Electric Generator work:

A
  • The polarity of the electro-motive force generates a current whose magnetic field opposes the change that generates it
  • When a magnet passed through the inside of a copper coil, a voltage difference was generated at the ends of the cable
  • It will only happen when the magnet is in motion
  • The sign of the voltage varied depending on the direction in which the magnet moved
  • The wind generator rotates because the air collides with its blades and generates a torque with respect to the shaft, which generates energy
  • The hydroelectric plants allow water that is in height to fall on turbines, forcing them to turn and generate energy
  • Nuclear power plants produce a large amount of heat that is used to heat water which when evaporated, expands its size and being guided by the pipes, spun by a turbine
  • The generators use a linear movement and the other generators have a circular motion
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2
Q

Features of a Turbine

A
  • Made of blades that rotate around a central haft eg wind turbine
  • A liquid or gas flows through the blades to make them spin and power the turbine shaft
  • Jet engines are turbines that run on kerosene
  • Gas turbines burn natural gas to power ships
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3
Q

What does the Faraday’s first law of electromagnetic induction state?

A

Faraday’s first law of electromagnetic induction states that a changing magnetic field will induce an electric current in a conductor.

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4
Q

Consider the following statement, “A generator creates electricity.”
Is this statement accurate? Why/why not?

A

This statement is accurate because as the generator spins it produces energy which is the source for powering electricity.

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5
Q

How does the portable radio recharge its batteries?

A

This portable radio uses a combination of solar cells and a hand-turned dynamo to recharge its batteries.

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6
Q

How can bikes run their front lights?

A

Bikes can use hub dynamos or bottle dynamos to generate the current needed to run their front lights.

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7
Q

Faraday’s Law of Induction: (rule)

A

ε = - dΦB/df

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8
Q

Faraday’s Law of Induction explanation:

A
  • Faraday’s law of induction tells us that the electro-motive force generated is equal to the derivative of the magnetic field with respect to time
  • The e stands for electro-motive force, which is equivalent to the voltage that will be generated in the circuit
  • The fb and the top stands for the magnetic field flow which refers to the direction and force of the magnetic field
  • Both d’s and the f at the bottom is the derivative which is a variation in time
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9
Q

Features of a Generator

A
  • Central shaft, but magnets wound with wire are mounted on it
  • The shaft and magnets make up the generator rotor
  • Around shaft and magnets are stationary coils of wire that make up the generator stator
  • When the shaft rotates, the magnets of the rotor produce magnetic fields that pass over the coils of wire in the stator, generating an electrical current in them
  • The generators always have magnetic fields passing over coils of wire to produce electric current
  • They generate power for the electric grid in power stations
  • They produce the electricity required for lights and electric control systems
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