White Board Work – Grade 10
Physics
02nd May 2023
VacationUnit – Special – Light Waves (LW).
Reference Book – MYP Physics – Years 4 & 5
A Concept Based Approach
Oxford University Press Publication (2018)
by
William Heathcote
Physics
Today’s Task
02nd May 2023
We will go through the
UP on Unit – 3 – LW - and its relevant
KC
RC
GC
GE
SOI
FQs
CQs
DQs
ATL Skills
Criteria - A & D
SL & LO
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Physics
Today’s Task
2 May 2023
Preparation for the following Criteria: Criterion – A – Knowing & Understanding
Criterion – D – Reflecting on the Impacts of Science
Physics
Today’s Task
03rd May 2023
Preparation for the following Criteria: FA 1 - criterion A
TBD in July 2023
FA 2 - Criteria B & C
TBD in July 2023
SA - Criteria A, B & C
TBD in July 2023
Today’s Task
Wave Symbol is same for both SW/LW and LW/TW.
Wave Length Symbol is again same ƛ (Lambda)
ƛ = 2.5 m
Amplitude = 0.3 m
Speed = V = 1.4 m / s
2
Time taken for One Wave = Period of Wave = T (second)
V=fƛ
T = 1 / f ====> f = 1/ T
V = Distance / Time = ƛ / T
1.4 = 2.5 / T=====> 1.4 (T) = 1 (2.5)
T = 2.5 / 1.4 = 1.8 s
Therefore F = Frequency = 1 / T = 1/1.8 = around 0.5
F = f = .63 = 1 with SF as ONE
8th May 2023
Physics
Similar Properties of LW & SW
1) Interference of Light Waves same as that of SW
For crest + crest 🡺 Constructive Interference of LW
or
trough + trough ⇒ Constructive Interference of LW.
It is similar to that of SW, where Construction is due to,
compression + compression
or
rarefaction + rarefaction ⇒ SW
3
Otherwise for
Destructive Interference of LW/SW,
Crest + Trough OR Trough + Crest
Compression + Rarefaction
or
Rarefaction + Compression
2) Diffraction of LW same as that of SW ⇒
Happens through a
PIN-Hole, whilst bending around the corner/hole/slit …
3) Reflection (R) of Light Waves same as that of SW
Angle i = Angle R
4) Refraction
(r) of Light Waves same as that of SW
When a light ray is incident from Rarer (Vacuum) Medium
To
Denser Medium
Angle i Greater than the Angle r
OR
r Less than i
R.I = Refractive Index = n = (Sini/Sinr)
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OR
n = Speed of Light in air or Vacuum (C) / Speed of Light in other Medium (V)
n = 3 X 108 / V,
Where V 🡺 Speed of Light in a given Denser Medium.
“n” Greater than 1 for Denser Medium.
Physics
Today’s Task
8th May 2023
Concept of Polarization
This is the property, which is not applicable to the
Sound Waves (SW)
NOTE on FAs & SAs
It is TBD in July 2023.
Numerical: 1LW Enters from Air to Glass with an angle of 60 Degree.
If the angle of refraction is 45 degrees and the speed of
light in Air is 3 X 108 m / s.
Then find
R. I
&
Speed of Light in Glass.
5
Physics
Property: - REFRACTION
9th May 2023
R. I = n = C / V
C = 3 X 108 m / s
V=?&N=?
i = 60
r = 45
For Light from Rarer to denser,
R . I = (Sini) / (Sin r)
R. I = Sin 60o / Sin 45o = 0.87 / 0.71 = 1.23
Test Method of Calci 🡺 Sin 300 = 0.5
n=C/V
In other words,
1.23 = 3 X 10 8 / V
1. 23 x V = 1 x 3 X 10 8
V = 3 X 10 8 / 1. 23 = (3/1.23) x 108 = 2.44 x 10 8 m /s
Thus,
R. I of Glass = n = 1.23
&
Speed of Light in Glass = V = 2.44 x 10 8 m /s
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Numerical: 2LW Enters from Air to Glass with an angle of 50 Degree.
If the angle of refraction is 30 degrees and the speed of
light in Air is 3 X 108 m / s.
Then find
R. I &
Speed of Light in Glass.
Today’s Task
LW ===>
V = frequency x Lamda = f x ƛ = n x ƛ
R I = C (Rarer) / V ( denser)
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C = 3 X 10 8 m /s = Speed of Light / EM Spectrum.
Types of EM Spectrum = 7
Highest frequency = Gamma = Lowest wavelength
Lowest frequency = Radio Waves = Highest wavelength
Physics
15th May 2023
Today’s Class with Last Task
Investigation Skills Based on the Criterion B & C.
How to get Multiple Images using TWO Mirrors.
Just like a resistor mirror also has certain properties.
Formula: Number of Images (N) = [360 / x ] – 1.
N = [360 / x ] – 1.
X🡺 is the angle between the two mirrors in degrees.
Verify through Investigation skills: 8
For Multiple Images
Use two plane mirrors.
UNFOLD two joined mirrors.
Then Angle between them is = 180o. = A
No of images = 1 = N
Formula ⇒ N = (360o / A) - 1 = (360o / 180o ) - 1 = 1
===> Angle = 45o
DIY
If A = 30o ====> N = ?
If A = 45o ====> N = ?
If A = 60o ====> N = ?
If A = 90o ====> N = ?
If A = 120o ====> N = ?
If A = 140o ====> N = ?
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