Apps-On-Physics/C2/Reflection-and-Refraction/English - Revision history

Madhurig at 12:51, 31 July 2020

2020-07-31T12:51:08Z

Madhurig at 12:37, 31 July 2020

2020-07-31T12:37:52Z

Karwanjehimanshi95 at 16:47, 20 June 2020

2020-06-20T16:47:50Z

Madhurig at 10:37, 11 June 2020

2020-06-11T10:37:37Z

Madhurig at 13:37, 10 June 2020

2020-06-10T13:37:52Z

Show changes

Madhurig at 12:42, 10 June 2020

2020-06-10T12:42:56Z

Show changes

Karwanjehimanshi95 at 11:56, 28 May 2020

2020-05-28T11:56:50Z

Karwanjehimanshi95 at 11:43, 28 May 2020

2020-05-28T11:43:25Z

Karwanjehimanshi95: Created page with " {|border=1 |- || '''Visual cue''' || '''Narration''' |- || '''Slide Number 1''' '''Title slide''' || Welcome to the Spoken Tutorial on '''Reflection and Refraction'''. |- ||..."

2019-12-19T09:33:55Z

Created page with " {|border=1 |- || '''Visual cue''' || '''Narration''' |- || '''Slide Number 1''' '''Title slide''' || Welcome to the Spoken Tutorial on '''Reflection and Refraction'''. |- ||..."

New page

{|border=1
|-
|| '''Visual cue'''
|| '''Narration'''
|-
|| '''Slide Number 1'''

'''Title slide'''
|| Welcome to the Spoken Tutorial on '''Reflection and Refraction'''.
|-
|| '''Slide Number 2 '''

'''Learning Objectives'''
|| In this tutorial, we will demonstrate,

'''Refraction of Light '''and

'''Reflection and Refraction of Light Waves Apps.'''
|-
|| '''Slide Number 3'''

'''System Requirements'''
|| Here I am using,

Ubuntu Linux OS version 16.04

Firefox web browser version 62.0.3
|-
|| '''Slide Number 4'''

'''Pre-requisites'''

'''https://spoken-tutorial.org/'''
|| To follow this tutorial, learner should be familiar with '''Apps on Physics'''.

For the pre-requisites tutorials please visit this site.

|-
|| '''Slide Number 5'''

'''Learning Goals'''
|| Using these '''Apps''', we will

* Demonstrate reflection and refraction of a light ray.

* Change the medium and angle of incidence to verify Snell's law.

* Demonstrate the formation of total internal reflection.

|-
|| '''Slide Number 6'''

'''Learning Goals'''
||
* Explain the formation of a critical angle.

* Calculate the value of critical angle.

* Explain reflection and refraction of waves by Huygens’ principle.

|-
|| '''Slide Number 7'''

'''Link for Apps on physics. '''

'''https://www.walter-fendt.de/html5/phen/'''
|| Use the given link to download the '''Apps.'''

|-
|| Open the '''Downloads '''folder.
|| I have downloaded the '''Apps on Physics '''to my '''Downloads''' folder.

|-
|| Right click on '''pulleysystem_en.htm''' file.

Select the option '''Open With Firefox web Browser''' option.

Cursor on the '''App'''.
|| Right click on '''refraction_en.htm '''file.

Select the option '''Open With Firefox web Browser.'''

'''Reflection and Refraction of Light App''' opens in the browser.

|-
|| Cursor on the interface.
|| The''' App '''shows reflection and refraction of light through a given medium.

|-
|| Point to air and water on the interface
|| The default media are air and water.

|-
|| Point to air.

Point to water.
|| Note that the medium with lesser refractive index is shown in white background.

The medium with greater refractive index is shown in blue background.

|-
|| Point to the light that has been incident.
|| Light from the top left corner, strikes the boundary surface of the two media.

|-
|| Point to both reflection and refraction angles.
|| It shows reflection and refraction.

|-
|| Point to blue angels
|| Reflection is shown by the blue coloured angle.

|-
|| Point to black and blue angles.
|| Observe that the angle of incidence and reflection are the same.

|-
|| Point to the refraction.
|| Here we see the refraction of light.

|-
|| Show the phenomena with the motion of the cursor.
|| When light travels from rarer medium to denser medium, it bends towards normal.

|-
|| Cursor on the green panel.
|| On the green panel we have a choice to change a few parameters.

|-
|| Point to the drop downs.
|| Let us reverse the two media using the drop downs.

|-
|| Click on the first drop down and change the medium to water.
|| Select water as the upper medium.

|-
|| Click on second drop down.

Select air from the drop down.
|| Select''' '''air''' '''as the lower medium.

|-
|| Move the cursor to show the movements
|| Here the ray of light travels from denser to rarer medium.

The ray bends away from the normal.

|-
|| Click on both drop down to show the material medium.
|| Note that both the drop downs show the same material media.

|-
|| Point to each drop down.
|| Below the drop down, we see two text fields.

These are provided to enter the values of refractive indices.

|-
|| Enter the value 4 in the '''1st index of refraction '''and show the change.
|| Here we can also change the values manually between the range of 1 to 5.

|-
|| Click on '''F5''' key on the keyboard.
|| Press '''F5''' key on the keyboard to refresh the '''App'''.

|-
|| Change the values from 0.1 degrees to 90 degrees and show the changes.

Click on '''F5''' key on the keyboard to refresh and show the default value.
|| Next '''Angle of incidence''' can be changed from 0.1 degrees to 90 degrees.

Press '''F5 '''key to see the default value.

It shows 30 degrees.

|-
|| Point below the text fields.
|| Below the text fields '''App''' shows the '''Angle of reflection and refraction'''.

|-
|| Point to the graph.
|| Graph shows the angle of refraction with angle of incidence.

|-
|| Click and drag the angle of incidence.

Drag it slowly.
|| We can also change the angle of incidence by dragging this red coloured ray.

|-
|| Point and show the changes when the angle of incidence is changed.
|| Notice the change in angle of reflection and refraction.

Simultaneously observe the graph.

|-
|| Cursor on the interface.
|| Now from the graph we will learn the two cases of '''Snell’s law'''.

|-
|| '''Slide Number 8'''

'''Snell’s Law of Refraction'''

sin i / sin r = n21

“n21” is the refractive index of the second medium w.r.t first.
|| Before that let us state '''Snell’s law''' of Refraction.

Ratio of sine of angle of incidence to sine of angle of refraction is a constant.

n21 is the refractive index of the second medium with respect to first medium.

|-
|| '''Slide Number 9'''

'''Snell’s Law of Refraction'''

'''Case1: '''If''' '''n21 > 1, angle of refraction is less than angle of incidence.

'''Case2: '''If''' '''n21 < 1, angle of refraction is greater than angle of incidence.
|| Here are the 2 cases of '''Snell’s law'''.

1. If n21 is greater than 1, angle of refraction is less than angle of incidence.

2. If n21 is less than 1, angle of refraction is greater than angle of incidence.

|-
|| Edit the value of '''Angle of incidence''' to 20 degrees.
|| Change the '''Angle of incidence''' to 20 degrees.

Observe that the angle of refraction has changed to 14.9.

|-
|| Point to the graph and values of the angles.
|| This graph shows the first case of Snell’s law.

Here angle of incidence is greater than the

angle of refraction.

|-
|| Point to the value of refractive index of the second medium.
|| Observe that the light ray bends towards the normal.

|-
|| Cursor on the interface.
|| Let us see what happens, when incident ray passes from denser to rarer medium.

|-
|| Click on the first drop down and change the medium to diamond.
|| From the first drop down change the material medium to '''diamond'''.

|-
|| Point to show the refraction.
|| Notice that the light ray has bent away from the normal.

|-
|| Point to the graph.
|| This graph shows the second case of '''Snell’s law'''.

|-
|| Point to show Angle of refraction.
|| Here the angle of refraction is greater than the angle of incidence.

|-
|| Change the '''Angle of incidence''' to 30 degrees.
|| Increase the '''Angle of incidence''' to 30 degrees.

|-
|| Point to the refracted ray.
|| The refracted ray has bent still more further away from the normal.

|-
|| Change the '''Angle of incidence''' to 35 degrees.
|| Again increase the angle of incidence to

35 degrees.

In this case observe that the refraction is not possible.

|-
|| Point to the reflected ray.
|| Here the incident ray is totally reflected.

|-
|| Cursor on the interface.
|| This phenomenon is known as total internal reflection.

Here the critical angle is formed.

|-
|| Point to the Critical angle.
|| The critical angle for diamond and water is 33.3 degrees.

|-
|| '''Slide Number 10'''

'''Critical angle'''

ic<nowiki>= sin</nowiki>-1(n2/n1)

ic<nowiki>= Critical angle</nowiki>

n1<nowiki>= Refractive index of first medium</nowiki>

n2<nowiki>= Refractive index of the second medium</nowiki>
|| Now we will calculate the critical angle using the formula.

|-
|| '''Slide Number 11'''

'''Tabular column'''
|| Let us make a tabular column to calculate critical angle for two different media.

|-
||
|| Here I have calculated the critial angle for diamond and water.

|-
|| Point to the on the interface Critical angle.
|| The calculated value is comparable to the value shown in the '''App'''.

|-
|| '''Slide Number 12'''

'''Tabular column'''

|| Now enter these values in the table.

|-
|| Change the upper medium to water and lower medium to air.
|| Next change the upper medium to '''water''' and lower medium to '''air'''.

|-
|| '''Slide Number 13'''

'''Tabular Column'''

Show one glimpse of the table
|| Note the refractive indices for both the media.

|-
|| Show the calculation''' '''for critical angle on a text-box or on a png.
|| Then calculate the critical angle using the above formula.

|-
|| Point to show the values.
|| Observe that the values are comparable.

|-
|| '''Slide Number 14'''

'''Tabular column'''
|| Note these values in the table.

|-
|| '''Slide Number 15'''

'''Assignment '''

Show the incomplete table.
|| As an assignment
* Note the values of refractive indices for the following media from the '''App'''.

* Calculate the critical angle for the two media.

* Compare the values with the ones shown in the '''App'''.

|-
|| Cursor on the interface.
|| Now we will move on to the next '''App'''.

|-
|| Right click on '''refractionhuygens_en.htm'''<<

'''Open With Firefox Web Browser'''.
|| Right click on '''refractionhuygens_en.htm '''file.

'''Open With Firefox Web Browser'''.

The''' App '''opens in the browser.

|-
|| Highlight the main topic from the screen.
|| '''App''' shows '''Reflection''' and '''Refraction''' of light waves using '''Huygens''' principle.

|-
|| Click on the '''Restart''' button.
|| Click on the '''Restart''' button.

|-
|| Point to the wavefront.
|| Here the plane wavefront is incident diagonally on the boundary of the media.

|-
|| Click on the '''Next step''' button.
|| Click on the '''Next step''' button.

|-
|| Point to the box and scroll the slider.(Highlight the box)
|| Explanation of each step is provided in this text box.

|-
|| Point to the wavefronts.
|| Note the change in media, when the wavefront is incident on the boundary.

|-
|| Click on the '''Pause''' button.
|| Click on the '''Pause''' button.

|-
|| Point to the pink point on the boundary.
|| Observe the pink points on the boundary between the media.

Each pink point is the source of spherical wavefront.

|-
|| Point to the waves in '''Medium1 '''and '''Medium 2'''.
|| These generating waves in the '''Medium 1 '''and''' Medium 2''' are the wavelets.

|-
|| Click on the''' Resume''' button.
|| Click on the''' Resume''' button.

|-
||
|| Note that the waves in '''Medium 2''' move with less velocity as compared to '''Medium 1'''.

This is because, the medium 2 has higher refractive index.

So here the waves move with less velocity.

|-
|| Click on the '''Next step''' button.
|| Click on the '''Next step''' button.

|-
|| Click on the '''Pause''' button.
|| Click on the '''Pause''' button.

|-
|| Point to the line drawn.
|| Observe the tangent drawn to all these spherical waves.

This line, here is the source for the secondary wavefront.

|-
|| Points on the wavelets.
|| So, the points on every wavelet result in the formation of secondary wavefront.

|-
||
|| Here the values of '''Angle of incidence''', '''reflection '''and '''refraction '''are given.

|-
|| Click on the '''Resume''' button.
|| Click on the '''Resume''' button.

|-
|| Point and show the direction of propagation of the red and blue waves.
|| Direction of propogation changes when waves move from medium 1 to medium 2.

|-
|| Again click on the '''Next step''' button.
|| Again click on the '''Next step''' button.

|-
|| Point to direction of the propagation of waves.
|| Here the direction of the propagation of waves is shown.

|-
|| Click on the '''Pause''' button.
|| Click on the '''Pause''' button.

|-
|| Point and show the perpendicular lines.
|| Observe that these lines of propagation are perpendicular to the wavefronts.

|-
|| Click on the '''Resume''' button.
|| Click on the '''Resume''' button.

|-
|| Change '''Angle of incidence '''<nowiki>= 60 degrees.</nowiki>
|| Change the '''Angle of incidence '''to 60 degrees.

|-
|| Click on the '''Next step'''.
|| Click on the '''Next step '''button.

|-
|| Point the series of waves.
|| Here we can see a series of wavefronts that are incident on boundary surface.

|-
|| Cursor on both mediums.
|| Observe the speed and wavelength of wavefronts in both the media.

|-
|| Point to the denser medium.
|| The wavelength and speed of the wavefront decreases in the denser medium.

But the frequency of the plane wavefronts remains the same.

|-
|| make the refractive index of 1 to 2 and refractive index of 2 to 1.
|| Let us reverse the refractive indices and observe the formation of wavefronts.

|-
|| Point to the wavefronts.
|| Here the speed of the wavefront decreases, as it moves from denser medium.

|-
|| Cursor on the interface.

Point to show the critical angle.
|| This shows the total internal reflection.

Here the incident wavefront is completely reflected and not refracted.

This results in the formation of critical angle.

|-
|| '''Slide Number 16'''

'''Assignment'''

Change the refractive index values of both media as given in the previous '''App'''.

Observe the formation of wavefront and give an explanation.

|| As an assignment

Change the refractive index values of both media as given in the previous '''App'''.

Observe the formation of wavefront and give an explanation.

|-
||
|| Let us summarize

|-
|| '''Slide Number 17'''

'''Summary'''
|| Using these '''Apps''', we have
* Demonstrated reflection and refraction of a light ray.

* Changed the medium and angle of incidence to verify Snell's law.

* Demonstrated the formation of total internal reflection.

|-
|| '''Slide Number 18'''

'''Summary'''
||
* Explained the formation of critical angle.

* Calculated critical angle.

* Explained reflection and refraction of waves by Huygens’ principle.

|-
|| '''Slide Number 19'''

'''Acknowledgement'''

These Apps are created by Walter-fendt and his team.
|| These '''Apps''' were created by Walter-fendt and his team.

|-
|| '''Slide Number 20'''

'''About the Spoken Tutorial project.'''

|| The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

|-
|| '''Slide Number 21'''

'''Spoken Tutorial workshops.'''

|| The '''Spoken Tutorial Project '''team,

conducts workshops and gives certificates.

For more details, please write to us.

|-
|| '''Slide Number 22'''

'''Forum for specific questions:'''

Do you have questions in THIS Spoken Tutorial?

Please visit this site

Choose the minute and second where you have the question.

Explain your question briefly.

Someone from our team will answer them.
|| Please post your timed queries in this forum.

|-
|| '''Slide Number 23'''

'''Acknowledgement'''
|| Spoken Tutorial Project is funded by MHRD Government of India.

|-
||
|| This is Himanshi Karwanje from IIT Bombay

Thank you for joining.

|-
|}

@@ Line 57: / Line 57: @@
 |-
 || Open the '''Downloads '''folder.
-|| I have downloaded the '''Apps on Physics''' to my '''Downloads''' folder.
+|| I have already downloaded the '''Apps on Physics''' to my '''Downloads''' folder.
@@ Line 108: / Line 108: @@
 |-
-|| Point to blue angels
+|| Point to blue angles.
 || Reflection is shown by the blue coloured angle.

@@ Line 443: / Line 443: @@
 || Observe the tangent drawn to all these '''spherical waves'''.
-This line, here is the source for the secondary '''wavefront'''.
+This line, here is the source of the secondary '''wavefront'''.
 |-
 || Points on the wavelets.
-|| So, the points on every wavelet result in the formation of secondary '''wavefront'''.
+|| So, the points on every wavelet results in the formation of secondary '''wavefront'''.
 |-
@@ Line 559: / Line 559: @@
 Verified '''Huygens' principle'''.
 |-
@@ Line 573: / Line 572: @@
 '''About the Spoken Tutorial project.'''
 || The video at the following link summarizes the Spoken Tutorial project.
@@ Line 585: / Line 582: @@
 '''Spoken Tutorial workshops.'''
-|| The&nbsp;'''Spoken Tutorial Project&nbsp;'''team,
+|| The '''Spoken Tutorial Project'''team,
 conducts workshops and gives certificates.

@@ Line 526: / Line 526: @@
 '''Assignment'''
-Change the refractive index values of both media as given in the previous '''App'''.
+Change the refractive index values of both media as given in Refraction of Light '''App'''.
 Observe the formation of '''wavefront''' and give an explanation.
@@ Line 532: / Line 532: @@
 || As an assignment
-Change the refractive index values of both media as given in the previous '''App'''.
+Change the refractive index values of both media as given in Refraction of Light '''App'''.
 Observe the formation of '''wavefront''' and give an explanation.

@@ Line 177: / Line 177: @@
 |-
 || Point below the text fields.
-|| Below the text fields '''App''' shows the '''Angle of reflection and refraction'''.
+|| Below the text fields '''App''' shows the '''Angle of reflection''' and '''refraction'''.
 |-
@@ Line 211: / Line 211: @@
 Ratio of '''sine''' of angle of '''incidence''' to '''sine''' of angle of '''refraction''' is a constant.
-n<sub>21 </sub>is the refractive index of the second medium with respect to first medium.
+n<sub>21 </sub>is the refractive index of second medium with respect to first medium.
 |-

@@ Line 494: / Line 494: @@
 |-
 || Point the series of waves.
-|| Here we can see a series of wavefronts that are incident on boundary surface.
+|| Here we can see a series of wavefronts that are incident on the boundary surface.
 |-
@@ Line 619: / Line 619: @@
 ||
 || This is Himanshi Karwanje from IIT Bombay
 Thank you for joining.
 |-
 |}

@@ Line 13: / Line 13: @@
 '''Learning Objectives'''
-|| In this tutorial, we will demonstrate,
+|| In this tutorial, we will learn to,
-'''Refraction of Light '''and
+Simulate reflection and refraction of a light ray.
 |-
 || '''Slide Number 3'''
 '''System Requirements'''
@@ Line 28: / Line 39: @@
 Firefox web browser version 62.0.3
 |-
-|| '''Slide Number 4'''
+|| '''Slide Number 5'''
 '''Pre-requisites'''
@@ Line 38: / Line 49: @@
 |-
-|| '''Slide Number 5'''
+|| '''Slide Number 6'''
-'''Learning Goals'''
+'''Link for Apps on physics. '''
-|| Using these '''Apps''', we will
-* Demonstrate reflection and refraction of a light ray.
+'''https://www.walter-fendt.de/html5/phen/'''
+|| Use the given link to download the '''Apps.'''
-* Change the medium and angle of incidence to verify Snell's law.
-−
-* Demonstrate the formation of total internal reflection.
 |-
-|| '''Slide Number 6'''
+|| Open the '''Downloads '''folder.
+|| I have downloaded the '''Apps on Physics '''to my '''Downloads''' folder.
-'''Learning Goals'''
-||
-* Explain the formation of a critical angle.
-−
-* Calculate the value of critical angle.
 |-
 || '''Slide Number 7'''
-'''Link for Apps on physics. '''
+'''Apps on Physics'''
-'''https://www.walter-fendt.de/html5/phen/'''
+'''Refraction of Light '''and
-|| Use the given link to download the '''Apps.'''
 |-
@@ Line 548: / Line 548: @@
 '''Summary'''
 || Using these '''Apps''', we have
-* Changed the medium and angle of incidence to verify Snell's law.
+Simulated reflection and refraction of a light ray.
-* Demonstrated the formation of total internal reflection.
+Changed the medium and angle of incidence to verify '''Snell's Law'''.
 |-
@@ Line 558: / Line 559: @@
 '''Summary'''
-||
+|| Calculated the value of critical angle.
-* Explained the formation of critical angle.
-* Calculated critical angle.
+Verified '''Huygens' principle'''.
 |-