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1) Law of Wave propagation
( V = υ × λ)
If a wave moves by velocity ( V ) covers a
distance equal the wave length ( λ ) so it
will takes time equal the periodic time ( T )
to travel this distance
Then
X
λ
V= =
t
T
𝟏
As 𝛖 =
2) Snells law
n1SinӨ1 = n2 Sinθ2
If we have 2 mediums has absolute
( 𝐕 n=1 ,n2𝛖and×the𝛌)speed of light
refractive index
in them is V1 , V2
n1 =
n2
So
n1
C
V1
=
andn2 =
C V1
C V2
𝐬𝐨
𝐓
So
From 1n2 =
V = 𝜐× λ
n2
n1
V1
V2
C
V2
=
=
V1
V2
Sin ∅1
Sinθ2
Then
3) Laws of Prism
( A = ∅2
1n2 =
+ θ1)
V1
Sin ∅1
n2
=
=
V2
Sinθ2
n1
So
n1SinӨ1 = n2 Sinθ2
- In the quadrilateral( XYZW)
So the sum of angles (A) and (e) is 180
A + e = 180
1
- In triangle (YWZ)
e + ∅2 + θ1 = 180
From 1 and 2
A = ∅2 + θ1
2
4) Laws of Prism
5) Refractive index of a glass
prism at minimum deviation
α = ∅1 + θ2 - A
α +A
Sin [ o ]
Sin ∅
2
n=
=
A
Sinθ
Sin [ ]
In triangle (PYW)
2
α = 1 +2
- ∅1 = θ1 + 1
So 1 = ∅1 - θ1
- θ2 = ∅2 + 2 So
2 = θ2 - ∅2
From 1 and 2
α = ∅1 - θ1 + θ2 - ∅2
α = ∅1 + θ2 - (∅2 + θ1)
So
α =∅1 + θ2 - A
equation ( 2 )
1
1- Angle of incidence ∅1 = angle of
emergence θ2 (
∅1 = θ2 = ∅o )
2
2- Angle of 1st refraction θ1 = angle of 2nd
incidence ∅2 ( θ1 = ∅2 = θo )
asA = ∅2 + θ1 = 2 θo
θo =
So
A
2
1
asα = ∅1 + θ2 - A = 2 ∅o + A
So
∅o =
αo + A
2
2
Then
𝛂 +𝐀
𝐒𝐢𝐧 [ 𝐨 ]
𝐒𝐢𝐧 ∅
𝟐
𝐧=
=
𝐀
𝐒𝐢𝐧𝛉
𝐒𝐢𝐧 [ ]
𝟐
5) Laws of thin prism
𝐧=
𝛂𝐨 + 𝐀
- 𝛂𝐨 = 𝐀 ( 𝐧 − 𝟏)
𝐀
𝐒𝐢𝐧 ∅
𝐧=
=
𝐒𝐢𝐧𝛉
As the angles[
𝛂𝐨 + 𝐀
𝟐
𝛂𝐨 + 𝐀
𝐒𝐢𝐧 [
𝟐
𝐀
]
𝐒𝐢𝐧 [ 𝟐 ]
𝐀
]and[ ]is so small so
𝟐
𝐧=
𝛂𝐨 + 𝐀
𝟐
𝐀
𝐒𝐢𝐧 [ 𝟐 ]
]
=
[
So
𝜶𝒐 + 𝑨
𝑨
𝜶𝒐 = 𝑨 ( 𝒏 − 𝟏)
𝒏=
and
𝛂𝐨 + 𝐀
𝟐
𝐀
[𝟐]
𝐏= 𝛒𝐠𝐡
𝐅𝐠
𝐀
𝐦 𝛂×𝐨 +𝐠𝐀
- 𝛂𝐨 = 𝐀 ( 𝐧 − 𝟏)
𝐏𝐧
==
𝐀𝐀
𝛒 × 𝐕𝐨𝐋 × 𝐠
𝐏=
𝐀
𝛒 × 𝐀×𝐡 ×𝐠
𝐏=
𝐀
𝐏=
- The sine of the angle = the angle
𝐒𝐢𝐧 [
6) Calculating the pressure (P)
at a point inside a liquid
]
𝐏= 𝛒𝐠𝐡
What is the function ( importance ) of
Fiber optics
( optical fiber )
1- Used to transmit light without much loses
2- They are used in medicalexaminationEx (endoscopes )
3- They are used in operativesurgery with laser beam
4- They are used in communication with laser
5- Transmit light to parts hard to reach in our body like the stomach
Reflecting prism:
1- It is used to change the path of light rays by 90o or 180o
2- It is used in optical instruments like periscope in submarines and
in binoculars
Cryolite
( Aluminum fluoride
- Magnesium
fluoride )
- To avoid any reflection loses on the reflecting prism
Thin prism
U - shape tube
- To determine the density of liquid by knowing he density of other
liquid insoluble in it
Mercury Barometer: 1- Measures the atmospheric pressure
2- Measure the height of a building
Manometer
1- Measures the pressure of a gas enclosed in a reservoir ( Pg)
2- Measures the difference between the pressure of an enclosed
gas and the atmospheric pressure (∆P )
Pascal’s principle
1- Hydraulic press
2- Dentist’s chairs
3- Hydraulic brake
pressure gauge
1- It is used to measure the Air pressure inside a car tire
What is the Factors each depends on
(importance ) of
Frequency ( υ )
𝛖=
𝐍
𝟏
𝐕
= =
𝐭
𝐓
𝛌
Wave velocity ( V )
𝐕=
𝐝
= 𝛖×𝛌
𝐭
Wave length ( λ )
𝛌=
1- source of waves
2- Wave length 𝜆 ( inversely relation )
3- Periodic time T ( inversely relation )
4- Wave velocity v ( direct relation )
1- Type of medium
2- Wave length 𝜆 (direct relation )
3- Frequency υ ( direct relation )
1- Frequency υ ( inversely relation )
2- Wave velocity v ( direct relation )
𝐝
𝐕
=
𝐍
𝛖
The distance between
2 successive fringes
(∆y) in Young’s
double slits
experiment
1- the distance between the 2 slits ( d ) ( inversely relation )
2-the distance the 2nd screen and the observation screen( R)
(direct relation )
3- Wave length of the used light source 𝜆 ( inversely relation )
The critical angle
1- the absolute refractive index of the high dense medium ( n )(
inversely relation )
𝟏
𝐒𝐢𝐧 ∅𝐜 =
𝐧𝟏
Relative refractive
index
- The ratio between the velocity of the light in the 2 mediums
Absolute refractive
index
- The ratio between the velocity of the light in the air sand the
velocity of the light in the other medium
The angle of deviation
in the triangular prism 1- angle of incidence of the light ray on the prism
2- angle of emergence of the light from the prism
3- Apex angle of the prism
The angle of deviation
in the thin prism
𝛂𝐨 = 𝐀 ( 𝐧 − 𝟏)
1- Apex angle of the prism
2- refractive index of the prism material
Density ( ρ )
1- Atomic weights ( type of material )
2- Inter-atomic or intermolecular spaces ( inversely relation )
3- Temperature ( inversely relation )
Pressure ( P )
1- the surface area (A) ( inversely relation )
2- The acting Force ( F ) (direct relation )
𝐏=
𝐅
𝐀
the pressure at a point
inside a liquid ( P )
𝐏= 𝛒𝐠𝐡
1- the depth of that point (h) (direct relation )
2- the density of the liquid (ρ) (direct relation )
3- the Free falling acceleration ( g ) (direct relation )
What is the Measuring unit of
(importance ) of
Frequency ( υ )
Cycle
Hertz ,
Second
,
Wave length ( λ )
meter
Amplitude (A)
meter
meter
Wave velocity ( V )
Second
,
second -1
Hertz × meter
Relative refractive index
No measuring unit
Absolute refractive index
No measuring unit
Density ( ρ )
Kilogram
meter3
relative density ( ρ` )
Pressure ( P )
Gram
Centimeter3
No measuring unit
Newton
meter2
mechanical advantages of
hydraulic press
,
( Pascal ) ,
Kilogram
meter × second2
, Bar ,
No measuring unit
Kilogram
meter3
, cmHg
What is the scientific idea of each
Fiber optics
( optical fiber )
Total internal refection of light
Reflecting prism:
Total internal refection of light
Endoscope
Total internal refection of light
periscope
Total internal refection of light
Mirage
Total internal refection of light
U - shape tube
- The pressure at the points at the same horizontal plane is the
same
Mercury Barometer: - The pressure at the points at the same horizontal plane is the
same
Manometer
- The pressure at the points at the same horizontal plane is the
same
1- Hydraulic press
2- Dentist’s chairs
3- Hydraulic brake
- The pressure at the points at the same horizontal plane is the
same
Definition
1- Mechanical waves: they are waves (disturbance) that need medium to propagate ( travel )
through
2- The waves: it is the disturbance that spread and carries a long energy
3- The displacement: it is the distance made by the vibrating body at any instant from its rest
position or ( its equilibrium origin )
4- The amplitude: It is the maximum displacement of the vibrating body away from its rest
point
- it is the distance between 2 points along the path of the vibrating object where its velocity at
one point is maximum and at the other point is zero
5- The complete vibration: it is the motion of the vibrating body by a fixed point along its
path 2 successive times in the same direction and displacement ( at same phase ) through the
interval of time
6- Frequency ( F ) : it is the number of complete vibrations ( oscillations ) made by the
vibrating body in 1 second
𝛖=
𝐍
𝐭
7- Periodic time ( T ) :
- It is the time taken by the vibrating body to make one complete vibration
- It is the time taken by the vibrating body to pass by the same point along its path 2successive
times in the same direction and the same displacement
𝐓=
𝐭
𝟏
=
𝐍
𝛖
8- Simple harmonic motion: it is the simplest form of the vibration motion
- The phase: it is the position and the direction of the motion of a particles of a medium in a
certain moment
9- Wave motion: it is motion result from the disturbance of the medium particles in definite
direction
- or it is disturbance that propagate in a medium
10- Transverse waves: it is the waves in which particles of the medium vibrates perpendicular
to the direction of the wave propagation
11- Crest: maximum displacement upward ( in the positive direction )
12- Trough: maximum displacement downward ( in thenegative direction )
13- The phase: it is the position and the direction of motion of a particle of medium in a certain
direction
14- Wave length of transverse wave: it is the distance between any 2 successive crests or
troughs
15- Longitudinal waves: it is the waves in which particles of the medium vibrates along the
direction of the wave propagation
16- Compression: it is the area in which particles of medium are of highest density
17- Rarefaction: it is the area in which particles of medium are of lowest density
18- Wave length of longitudinal wave: it is the distance between the centers of any 2
successive compressions or rarefactions
19- Wave length ( λ ) : it is the distance between any 2 successive points having the same
phase
- it’s the distance covered by the wave in one periodic time
20- Electromagnetic waves: they are transverse waves consist of electric field and magnetic
fields have the same phase and perpendicular to each other and to the direction of propagation
of the wave
21-Electromagnetic spectrum: it is the arrangement of electromagnetic waves according to
their wave length or frequency
22- Light reflection: it is the return (bouncing ) of the light waves in the same medium when it
hit a reflecting surface
23- First law of light reflection: Angle of incidence ( Ө ) = Angle of reflection ( θ )
24- Second law of light reflection: The incident light ray and the reflecting light ray and the
normal to the reflecting surface at the point of incidence all lie on the same plane perpendicular
to the reflecting surface
25- Incident light ray ( AC ) : it is the light ray which fall ( intersect ) with the reflecting
surface at point of incidence
26- Reflected light ray ( CB ) : it is the light ray which reflected from the reflecting surface at
point of incidence
27- Angle of incidence ( Ө ) : it is the angle between the incident ray and the normal
perpendicular at the reflecting surface at the point of incidence
28- Angle of reflection ( θ ) : it is the angle between the reflected ray and the normal
perpendicular at the reflecting surface at the point of incidence
29-Light refraction: it is the change of the direction ( path ) of the light ray when it pass the
separating surface between 2 transparent surfaces different in optical density
30- Optical density of medium: it is the ability of the transparent medium to refract the light
31- Angle of incidence ( Ө ) : it is the angle between the incident ray and the normal
perpendicular at the separating surface at the point of incidence
32- Angle of refraction ( θ ) : it is the angle between the refracted ray and the normal
perpendicular at the separating surface at the point of incidence
33- Separating surface: it is the surface separates 2 mediums with 2 different optical densities
34- Relative refractive index (1n2):it is the ratio between sine angle of incidence in the first
medium to sine angle of refraction in the second medium
- it is the ratio between the velocity of light in the first medium to the velocity of light in the
second medium
- it is the ratio between the absolute refractive index of the second medium to the absolute
refractive index of the first medium
𝟏𝒏𝟐 =
𝑽𝟏
𝑺𝒊𝒏 ∅𝟏
𝒏𝟐
=
=
𝑽𝟐
𝑺𝒊𝒏𝜽𝟐
𝒏𝟏
35- Absolute refractive index: it is the ratio between sine angle of incidence in the air or space
to sine angle of refraction in the medium
- it is the ratio between the velocity of light in the air or space to the velocity of light in the
medium
𝒏𝟏 =
𝑪 ( 𝑽𝒂 )
𝑺𝒊𝒏 ∅𝒂
=
𝑽𝟏
𝑺𝒊𝒏𝜽𝟏
36- Snell’s Law: the absolute refractive index of the medium of incidence times sine angle of
incidence equal the absolute refractive index of the medium of refraction time’s sine angle of
refraction
n1SinӨ1 = n2 Sinθ2
37- Interference of light: it result from superposing of the light waves produced from 2
sources having the same frequency and amplitude and the same direction of propagation and
phase
38- Coherent sound source: they are sources whose waves have the same phase and frequency
and amplitude
39- Interference fringes: they are dark and bright region produced from interference of 2
coherent waves
40- Diffraction of sound : change of the light waves path on straight lines when it pass through
narrow silt or by a solid sharp edge which cause interference of light waves to form dark and
bright fringes
41- Airy’s disk: it is bright spot formed on the observation screen by the light rays which
diffracted
42- Critical angle ( Өc ) : it is the angle of incidence in denser medium that is correspond to an
angle of refraction in the less dense medium = 90o
- it is the angle of incidence when light fall from high dense medium to less dense medium the
light pass tangent to the separating medium
43- Total internal reflection: when light fall from high dense medium to less dense medium
by angle of incidence greater than the critical angle the light reflect in the same medium where (
incident angle = reflecting angle ) without passing to the less dense medium
44- Deviation angle( α ) : it the angle between the extension of the incident light ray and the
extension of the emergent light ray
45- The angular dispersion: it is the angle between the extensions of the red and blue light
rays after their emergence from the thin prism
(αo)b- (αo)r = A(nb–nr )
46- The middle ( average ) deviation(αo)y: it is the angle of deviation of the yellow colored
light emergent from the thin prism
(𝛂𝐨 )𝐲 = 𝐀 (𝐧𝐲 − 𝟏 )
47- The dispersive power of the prism: it is the ratio between The angular dispersion of the
prism and the minimum angle of deviation of the yellow light color
𝛚𝛂 =
(𝛂𝐨 )𝐛 − (𝛂𝐨 )𝐫
𝐧𝐛 + 𝐧𝐫
=
(𝛂𝐨 )𝐘
𝐧𝐲 − 𝟏
48-Fluids: They are materials which can flow and can't take a fixed shape, but take the shape
of the container
49- Density: it is the mass per unit volume
𝛒=
𝐦
𝐕𝐨𝐋
50- Relative density (specific weight): it is the ratio between the density of any material and
the density of water at the same temperature
- it is the ratio between the mass of a certain volume of a substance and the mass of the same
volume of water at the same temperature.
( 𝛒` ) =
𝛒𝐬
𝐦𝐬
=
𝛒𝐰
𝐦𝐰
51- Pressure: it is the average force which acts normally at a unit area
𝐏=
𝐅
𝐀
52- Atmospheric pressure ( Pa ): it is the weight of the air column affecting a unit area m2
The pressure at a point inside a liquid:53The weight of a column of the liquid around that point, its cross section area 1 m2 and its
length equals the depth of that point from the liquid surface
54- The atmospheric pressure: it is the weight of the air column over a unit area at sea level
- It is difficult to measure the weight of the air column over the earth surface
55- Normal atmospheric pressure: it is the weight of a column of mercury whose height is
0.76 m and cross section area 1 m2 at 0 o c at sea level
56- Pascal's Principle: When a pressure is applied on a liquid enclosed in a container, the
pressure is transmitted in full to all parts of the liquid as well as the walls of the container
57- Mechanical advantage of a hydraulic press ( η ):
- The ratio between the forces generated by the large piston to the force applied on the small
piston
- The ratio between the area of the large piston to the area of the small piston
𝐅𝟐
𝐀𝟐
𝐫𝟐𝟐
𝐲𝟏
𝐕𝟐
𝛈 =
=
= 𝟐=
=
𝐟𝟏
𝐚𝟏
𝐘𝟐
𝐕𝟏
𝐫𝟏
Compare
Mechanical waves
they are waves ( disturbance ) that need
medium to propagate ( travel ) through
Electromagnetic waves
they are waves ( disturbance ) that don’t
need medium to propagate ( travel ) through
- can travel in space
Transverse and longitudinal
Transverse waves only
- water waves
- x ray waves
- sound waves
- radio waves
- light waves
Has low speed
High speed in vacuum= 3 × 108
Result from vibration of medium particles It result from propagation of electric field and
along or perpendicular to the direction of magnetic fields perpendicular in each other
wave propagation
and perpendicular to the direction of wave
propagation
Point of
comparison
Definition
Consist of
Wave length
Place of its
occurrence
Examples
Transverse waves
it is the waves in which particles of
the medium vibrates perpendicular
to the direction of the wave
propagation
crests and troughs
it is the distance between any 2
successive crests or troughs
In liquids and gases
light waves – Water waves
Both of them vibrates by simple
harmonic motion around their rest
position
Longitudinal waves
it is the waves in which particles of
the medium vibrates along the
direction of the wave propagation
compressions and rarefactions
it is the distance between the centers
of any 2 successive compressions or
rarefactions
In liquids , gases and solids
Sound waves
Point of
comparison
Definition
unit
Value
Relative refractive index
Absolute refractive index
- it is the ratio between sine angle of it is the ratio between sine angle of
incidence in the first medium to sine incidence in the air or space to sine
angle of refraction in the second
angle of refraction in the medium
medium
- Or it is the ratio between the
velocity of light in the first medium
to the velocity of light in the second
medium
- Or it is the ratio between the
velocity of light in the air or space to
the velocity of light in the medium
It has no measuring unit
- It could be greater than or less
than one
It has no measuring unit
It must be greater than one
1n2 =
Law
V1
Sin ∅1
=
V2
Sinθ2
Constructive interference
n1 =
C ( Va )
Sin ∅a
=
V1
Sinθ1
Destructive interference(nil amplitude
it results when the Crest of the first
wave meet the Crest of the second wave
or when the trough of the first wave
meet the trough of the second wave
it result when the Crest of the first wave meet
the trough of the second wave or when the
trough of the first wave meet the Crest of the
second wave
Reinforcementof light
disappearanceof light
( bright fringes is formed )
( bright fringes is formed )
The path difference between 2 waves is
m λ ( m is integer)
The path difference between 2 waves is =
( 0 , 1λ , 2λ , 3 λ … )
( m + ½ λ ) ( m is integer)
Point of comparison
Reflecting accuracy
Losing its ability of
reflection
Liquids
Prism
reflecting surfaces
Light is totally reflected by It is seldom to find a
100% accuracy
reflecting surface whose
efficiency is100%
This doesn’t happen to the
prism
Metallic surface after time
loses it luster and its ability of
reflection decreases
Gases
They aren’tcompressible
They are compressible
They have fixedvolume
They have nofixedvolume
They have nofixedshape
They have nofixedshape
Give reason
1- The water waves is Mechanical transverse waves
…………………………………………………………………………………………………
2- The Mechanical waves can’t transfer through space
…………………………………………………………………………………………………
3- The wave length increase by decreasing of the frequency
…………………………………………………………………………………………………
4- Spacemen speak by using wireless on the moon surface
…………………………………………………………………………………………………
5- The frequency increase 4 times if the periodic time decrease by ¼
…………………………………………………………………………………………………
6- We can’t hear sound of explosion on the sun surface but its light can reach us
…………………………………………………………………………………………………
7- All the electromagnetic waves are transverse only
…………………………………………………………………………………………………
8- The mechanical waves could be transverse or longitudinal waves
…………………………………………………………………………………………………
9- Radio waves is electromagnetic waves
…………………………………………………………………………………………………
10- The electromagnetic waves can travel through space
…………………………………………………………………………………………………
11 –The wave is a disturbance which transmits and transmits the energy in its direction of
propagation
…………………………………………………………………………………………………
12- When a disturbance affect water in container transverse waves formed at the surface
and longitudinal waves form at the bottom of the water
…………………………………………………………………………………………………
13- Sound travel inform of longitudinal waves in gaseous medium while it travel inform of
transverse and longitudinal waves in solid and liquid medium
…………………………………………………………………………………………………
14- Sound travels in solid materials faster than that in gases
………………………………………………………………………………………………….
15- Light waves is electromagnetic transverse waves
……………………………………………………………………………………………….
16- Light waves can travel in space
……………………………………………………………………………………………….
17- We see sun light and can’t hear explosion happen on its surface
……………………………………………………………………………………………….
18- We can see lighting before hearing thunder
……………………………………………………………………………………………….
19- Light has a wave nature
……………………………………………………………………………………………….
20- Gamma rays has ability of penetrating bodies more than infrared rays
……………………………………………………………………………………………….
21- The light ray which falls perpendicular on a reflecting surface reflects on it self
……………………………………………………………………………………………….
22- The relative refractive index could be greater or less than real one
……………………………………………………………………………………………….
23- The relative refractive index has no measuring unit
……………………………………………………………………………………………….
24 - The absolute refractive index has no measuring unit
……………………………………………………………………………………………….
25- The absolute refractive index always greater than the real one
……………………………………………………………………………………………….
26- It is easily to see your image on a glass of a window when its dark out side than when
its light out side
……………………………………………………………………………………………….
27- The light ray which falls perpendicular on a separating surface between transparent
medium (water surface ) passes without refraction
……………………………………………………………………………………………….
28- A monochromatic light source is used in Young’s experiment
……………………………………………………………………………………………….
29- The fringe in the center in Young’s experiment is always bright
……………………………………………………………………………………………….
30- The fringes become more clearly by decreasing the distance between the 2 splits
……………………………………………………………………………………………….
31- The absolute refractive index of air always equal the real one
……………………………………………………………………………………………….
32- The critical angle between 2 medium increases by decreasing the difference between
the absolute refractive index of the 2 mediums
……………………………………………………………………………………………….
33- The light which emit from under the water surface can not be seen in the air
……………………………………………………………………………………………….
34- Diamond is more brightness than glass
……………………………………………………………………………………………….
35- We see pen is bent or broken in a cup filled with water ( ground of swimming pool
appears nearer to us than its real place )
……………………………………………………………………………………………….
36- If we put a red light source in the center of a glass cube a square spot appears on a
screen put in front of the square cube and if we put a blue light source in the center of a
glass cube a circular spot appears on a screen put in front of the square cube
……………………………………………………………………………………………….
37- Prism is preferred to be used than the other reflecting surfaces ( mirrors ) in changing
path of light rays
……………………………………………………………………………………………….
38-The sides of the prism from which light rays fall on the prism or emerge from the
prism is coated with non reflecting layer of material like Cryolite ( Aluminum fluoride
and Magnesium fluoride ) whose refractive index is less than whose of glass
……………………………………………………………………………………………….
39- The outer layer of the optical fiber is covered with glass layer has absolute refractive
index lower than the absolute refractive index of the inner layer of the optical fiber
……………………………………………………………………………………………….
40- The optical fiber is used in transferring light to the parts hard to reach in our body
like the stomach
……………………………………………………………………………………………….
41- The sound diffraction is more observed than light diffraction
……………………………………………………………………………………………….
42- If a white light falls on a prism at the minimum deviation state it it splits into spectrum
colors
……………………………………………………………………………………………….
43- The rectangular glass prism can’t used in analyzing of light
……………………………………………………………………………………………….
44- The angle of deviation of the violet color is bigger than that of the red color
……………………………………………………………………………………………….
45- The density is a basic property of the matter
…………………………………………………………………………………………………
46- The density changes from one element to another
…………………………………………………………………………………………………
47- The density of a matter is changed by the change of the temperature
…………………………………………………………………………………………………
48- The relative density has no measuring unit
…………………………………………………………………………………………………
49-You can indicate the rate of charge of the car batteryby estimation of the density of its
electrolyte
…………………………………………………………………………………………………
50- The density of the electrolyte of the car battery decreases during discharging of the
battery
…………………………………………………………………………………………………
51- We can indicate anemia disease by measuring the density of the blood
…………………………………………………………………………………………………
52- We can indicate some diseases by measuring density of the urine
…………………………………………………………………………………………………
53-If you push a piece of foam under water and let it go, it will rise and float.
…………………………………………………………………………………………………
54- All the points that are found on the same horizontal plane inside a liquid have the
same pressure
…………………………………………………………………………………………………
55 –The locomotive cars and trucks use wide tires
…………………………………………………………………………………………………
56- The average sea level is constant for all connected seas and oceans
…………………………………………………………………………………………………
57- The base of a dam is thicker than its top
…………………………………………………………………………………………………
58- The pressure result from the a pointed high heel of a woman is more than that result
from elephant leg
………………………………………………………………………………………………….
59- The camel can move on desert however it has a big mass
…………………………………………………………………………………………………
60- The density changes from one element to another
…………………………………………………………………………………………………
61- The knife has a sharp edge and the needle has a sharp point end
…………………………………………………………………………………………………
62- The height of the mercury in the barometer doesn’t depend on its cross section area of
its tube
…………………………………………………………………………………………………
63-Mercury not water is used in the barometer
…………………………………………………………………………………………………
64- The density of the electrolyte of the car battery decreases during discharging of the
battery
…………………………………………………………………………………………………
65- Torricelli vacuum can be disappeared in the barometer
…………………………………………………………………………………………………
66- The pressure decrease when we move vertical upwards towards water surface
…………………………………………………………………………………………………
67- The man can’t fill the atmospheric pressure
…………………………………………………………………………………………………
68- All the points that are found on the same horizontal plane inside a liquid have the
same pressure
…………………………………………………………………………………………………
69 – The reading of the barometer on the top of the mountain is less than its reading on
the earth surface
…………………………………………………………………………………………………
70- Human bleeds from nose at the highest elevations
…………………………………………………………………………………………………
71- We should chewing gum in high places
…………………………………………………………………………………………………
72- It is preferred to use water manometer than mercury manometer in measuring small
pressure difference
…………………………………………………………………………………………………
73- The car tire turns hot when the difference in pressure of air inside it is low
…………………………………………………………………………………………………
74- The density of a matter is changed by the change of the temperature
…………………………………………………………………………………………………
75- Pascal's Principle is not applied on gases
…………………………………………………………………………………………………
76-Liquid obey Pascal principle
…………………………………………………………………………………………………
77- The oil in hydraulic press shouldn’t contains air bubbles
…………………………………………………………………………………………………
78- The hydraulic press isn’t used to multiply the energy
…………………………………………………………………………………………………
79- When you press a piston on a liquid enclosed in a tank the piston doesn’t move
…………………………………………………………………………………………………
Application
1) Optical fiber
- It is a thread – like hollow tube made of
transparent material (glass or plastic)
How does it work?
When the light falls on one of its ends by
incident angle greater than critical angle it
undergoes successive multiple number of
internal reflections until it emerges from
the other end so light can travels through it
in non straight line
3) Clinical analysis depends on
density of liquids of body
a- Measuring blood density:
- The normal blood density is
(1040 kg/m - 1060 kg/m )
a) Higher density indicates higher
concentrations of red blood cells.
b) Lower density (lower concentration of
red blood cells) indicates anemia.
b- Measuring urine density:
- The normal urine density is 1020 kg/m
Some diseases increase the
concentrations of salts in the urine, so the
density increases.
2) Mirage
A natural phenomenon takes place on the
hot days as paved roads appear as if they
are wet and an image of sky is made on
desert plains where palm trees or hills
appear inverted giving the illusion of water
Explaining:
1- On hot days air layers near earth surface
are heated and their density decreases and
their refractive index becomes smaller than
upper layers
2- When light ray falls from the upper air
layer to the lower air layer it refracts and
keeps deviating taking a curved path
3- When its incident angle becomes greater
than critical angle it under goes total
reflections and the curves go up and the
observer see it as if it is coming from under
the earth surface
4) Measuring density indicates
how well the car battery is
- When battery is discharged: the acid
reacts with lead forming lead sulphate on
the lead plates of the battery, so the
densityoftheelectrolyteislow due to the
consumption of the acid.
- When battery is charged:sulphate
groups liberate from the lead plates and
return to the electrolyte, so
thedensityoftheelectrolyteincreases.
5) Measuring the blood
pressure:
- Blood is a viscous liquid pumped through
a network of arteries and veins by the
muscular effect of the heart
Types of blood pressure:
a- Systolic pressure: the maximum blood
pressure (120torr) when the cardiac
(heart) musclecontracts to push the blood
from the left ventricle through the aorta
onto the arteries
b- Diastolic pressure: the minimum blood
pressure (80 torr) when the cardiac(heart)
musclerelaxes
6) Measuring the air pressure
inside a car tire:
a- When a tire is well inflated (under high
pressure): the area of contact with the
road is small (low friction force with the
road )
b- An underinflated tire (under low
pressure): the area of contact with the
road is large (the friction force with the
road increases) so the tire is heated
.