Maxwell's Equation

Maxwell's Equation

By Dr KEE CH

Lesson objectives:

1. Students will be able to describe Maxwell's Equations.

2. Students will be able to recognized that electromagnetic radiation is part of electromagnetic spectrum.

3. Students will be able to acknowledge the importance and implications of Maxwell's Equations.

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Revision (Wave)

Multiple Choice

Which letter represents wavelength?

• A
• B
• C
• D

Multiple Choice

Which letter represents amplitude?

• A
• B
• C
• D

Multiple Choice

Which wave has a greater frequency?

• A
• B

Multiple Choice

What is another name for wave height?

• Frequency

• Amplitude

• Wavelength

• Origin

Multiple Choice

What is measured from crest to crest or trough to trough?

• mediums

• resting position

• wavelength

• origin

Multiple Choice

If a wave has a greater frequency, what happens to the wavelength?

• increases

• decreases

• stays the same

Multiple Choice

If a wave has a greater frequency, what happens to number of waves per second?

• increases

• decreases

• stays the same

Multiple Choice

What is the amplitude of this wave?

• 2

• 3

• 6

• 10

Multiple Choice

What is the wavelength of this wave?

• 1

• 2

• 3

• 4

Multiple Choice

What property does the orange arrow (A) represent?

• Crest

• Trough

• Wavelength

Multiple Choice

What property does the green arrow (B) represent?

• Crest

• Trough

• Wavelength

Multiple Choice

This sound has high pitch, which means it has a higher frequency. This means when you hear the sound...

• More waves hit your ears per second

• Bigger waves hit your ears

• Less waves hit your ears per second

• Longer waves hit your ears

Multiple Select

All waves carry energy from one place to another, but some waves carry more energy than others. A leaf falling on water produces waves so small they are hard to see. An earthquake under the ocean can produce huge waves that cause great destruction.

What affects the energy of a wave? Select the 3 that apply.

• The energy in a wave is determined by amplitude, which is the distance from the rest position of a wave to the top or bottom.

• Large amplitude waves contain more energy.

• The energy in a wave is determined by frequency, which is the number of waves that pass by each second.

• The medium (material) moving along with the wave.

Multiple Choice

A disturbance that transfers energy from place to place through matter or space

• wave

• position

• time

• protein

Multiple Select

Frequency and period are closely related. Frequency is the inverse of period.

suppose the time from one crest to another (one crest to another is also known as "the period") is 5 seconds; what is the frequency?

Select the 2 that apply.

• .2

• 1/5

• .5

• 1/2

Multiple Choice

One hertz is equal to:

• 1 cycle per second

• 1 amplitude

• 1 frequency

• all the cycles in the wavelength

Multiple Select

The particles in cold air have less kinetic energy than the particles in warm air. this means that they collide less often and take longer to transmit a sound wave pulse. What is this an explanation of:

• the speed of mechanical energy

• the speed of sound

• the speed of electromagnetic energy

• the speed within a vacuum

Multiple Choice

Each wavefront expands in a sphere, spreading the energy across a larger area. This means that the energy per unit area of the wave decreases as it moves farther form its source, causing the loudness of the sound wave to decrease. This is an example of:

• energy of the sound wave changing as it moves farther away from the source.

• energy of the sound wave remaining constant as it moves farther away from the source.

• energy of the sound wave increases as it moves farther away from the source.

Multiple Choice

How are Electromagnetic waves different from Mechanical waves?

• EM waves have very short wavelengths

• EM waves transmit energy instead of matter

• EM waves can travel through the vacuum of space (without particles)

• EM waves can change direction by reflection

Multiple Choice

Wavelength and Frequency are related in that...

• they are always the same

• when one increases, the other decreases (inversely proportional)

• there is no correlation

• they both vary in an irregular pattern

What is Maxwell's Equations?

​4 complicated equations that describe the world of electromagnetics.

What is Maxwell's Equations?

1. ​Gauss' Law

2. Gauss' Magnetism Law

3. Faraday's Law

4. Ampere's Law​

Why is Maxwell's Equations important?

​Critical in understanding antennas and electromagnetics.

Light is an Electromagnetic Wave

Maxwell's Equations showed that the speed of an Electromagnetic Wave is 3.00 x 10⁸m/s

So what?

First to determine the speed of propagation of electromagnetic (EM) waves was the same as the speed of light - and hence to conclude that EM waves and visible light were really the same thing.

​Edpuzzle

Please click on the link​

Check your understanding

Multiple Choice

An electric field is produced by a separation of charges or by:

• a changing magnetic field

• a constant magnetic field

• a changing or constant magnetic field

Multiple Choice

A changing Electric Field will produce:

• a changing electric field

• a changing magnetic field

• a gravitational field

Multiple Choice

Maxwell's Equations consist of ________ equations.

• 1

• 2

• 3

• 4

Multiple Choice

Which of Maxwell's Equations allows you to figure out an equation for the electric field created by a distribution of charge?

• Gauss' Law

• Gauss' Law for Magnetism

• Faraday's Law

• Ampere's Law

Multiple Choice

Which of Maxwell's Equations describes an electric field can be created by a changing magnetic field?

• Gauss' Law

• Ampere's Law

• Faraday's Law

• Gauss' Law for Magnetism

Multiple Choice

Which of Maxwell's Equations describes a changing electric field can create a magnetic field

• Gauss' Law

• Ampere - Maxwell law

• Faraday's Law

• Gauss' Law for Magnetism

Open Ended

What is the key takeaway from today's lesson?