أهم 100 سؤال فى مراجعة مادة فيزياء لغات الجزء الثانى الصف الثالث ثانوي

من طرف **حنين الصمت** الجمعة 12 أبريل 2013, 9:33 pm

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أهم 100 سؤال فى مادة فيزياء لغات - الجزء الثانى

Second;multiple choice questions(M.C.Q)

5. In a longitudinal wave, the direction of vibrations of the
mediums Particles relative to the direction of propagation of the wave
is ……………………………

a)In the same direction

b) in perpendicular direction

c) in an inclined direction

6. The relation between frequency, wavelength and the velocity of waves propagation is……………………

الإجابة الصحيحة ( (d

7. The figure shows a transverse wave. The distances are measured
in centimeters and the time is measured in seconds Which of the
following describes the period, the wavelength ,the speed and the
frequency of the waves?

period Frequency wavelength Velocity Amplitude

a 20s 0.05Hz 1m 0.75m/s 4Cm

b 2 s 0.5Hz 0.3m 0.15m/s 4Cm

c 0.2s 5Hz 0.45m 50m/s 8Cm

Thired; Give reasons

1) Sound waves are mechanical waves.

Because, propagation of sound needs medium to propagate through it. i.e. it does not transfer through vacuum.

2) Light waves are transverse waves.

Because light waves propagate in the form of successive crests
and troughs. Making the particles of the medium oscillate about their
equilibrium position perpendicularly to the direction of its
propagation.

3) Sound waves propagate in air in the form of longitudinal waves only

Because, when sound waves propagate, the particles of air vibrate
in the same direction of the wave propagation. then successive
compressions and rarefactions takes place.

4) When the end of a stretched string is plucked once, a transverse wave pulse is created along the string.

Because the propagation of the pulse along the string acts to
make the particles of the string oscillate for a short distances about
their equilibrium position in a simple harmonic motion in a direction
perpendicular to the direction of the wave propagation taking the form
of successive crests and troughs .

5) When a mechanical wave pulse travels along a horizontal spring, it appears as longitudinal wave.

Because the particles of the spring displaced (oscillated)
parallel to the direction of the wave propagation in the form of
successive compressions and rarefactions.

6) When the frequency of a wave increased in a certain medium, its wave length is decreased.

As the condition required to propagate the longitudinal waves is
the vibration and the displacement of the medium particles about their
equilibrium positions which is available In all states of matter (solid
– liquid – gas), whereas the condition required to propagate the
transverse wave is the existence of pronounced attraction forces between
the particles which are available only in solids and liquids.

7) The wavelength of the transverse wave is the distance between two successive crests.

Since therefore the wavelength is inversely proportional to the frequency at constant velocity.

Cool

The longitudinal wave pulses along the string are regarded as one form of simple harmonic motion.

Because the distance between two successive crests, represent two successive points having the same phase.

9) Astronauts, on moon surface couldn’t hear their direct voices.

that because; sound is a mechanical wave which can not travel
through vaccum. therefore, it needs medium to propagate through it.

Fourth; Comparisons

1) Compare between each of the following:

1-The electromagnetic waves and the mechanical waves.

i-(two points only). ii-from the point of view of the propagation.

يظهر السؤال ثم تظهر الاجابة كالتالى بحيث يرسم الجدول وتملأ فيه
البيانات كالتالى يظهر الجزء الاصفر ثم الاخضر ثم السطور التى تليه
بالترتيب ثم يظهر الجزء الازرق كالتالى السطر الاول ثم يظهر الجزء A ثم
الصف الذى أمامه ثم الجزء B ثم الذى أمامه ثم الجزء C ثم الصف الذى أمامه
ثم الجزء D ثم الصف الذي أمامه

A)Electromagnetic waves

B)mechanical waves

1- Points of similarity

1- The particles of the medium vibrate around their equilibrium position.

2- The equation (V= ) can be applied to any known wavelength and frequency.

3- They all, under suitable conditions, can be reflected, refracted and diffracted, and exhibit the phenomenon of interference.

2- Points of differences

A)The propagation They do not necessarily need a medium through
which to travel and thus can travel in a vacuum It needs a medium to
propagate through which to travel.

B)Classification

They are all transverse waves. They are transverse waves or longitudinal waves.

c) Nature of the waves. (mode of the particles vibration)
Electromagnetic waves are created due to vibration of electric and
magnetic fields perpendicular to each other and perpendicular to the
direction of wave propagation .

(c) Mechanical waves are created due to vibration the particles
of the medium perpendicular to or in the same direction of propagation
.So these waves requires

1) A Source of disturbance, such as vibrator.

2) Kind of disturbance .that can transferred from the vibrator to the medium.

3) Kind of medium, that carries the disturbance (such as air, water….etc.)

D)Examples Light – Radio waves, X-rays, gamma rays.

T.V. waves, ultraviolet waves Sound, water waves, waves in a
stretched string and waves produced due to vibration of tuning fork.

2)The longitudinal and transverse waves, with respect to:

i-Particles vibration. ii- Wave shape.

iii- Wavelength. iv- Examples of the waves

A-Transverse waves

B-Longitudinal waves

1-Points of similarity

1- The particles of the medium vibrate around their equilibrium position.

2- All waves obey the same law of wave propagation that is. (v= )

3- All waves undergo reflection, refraction diffraction, and interference phenomena

2- 2-Points of differences

a)Mode of the particles vibration The particles of the medium
vibrate in a perpendicularly to direction of propagation of the wave
propagation The particles of the medium are vibrate along the direction
of propagation the wave.

b) the Structure

It consists of successive Crests and troughs It consists of successive Compressions and rarefactions.

c) Wave length The wavelength is equal to the distance between
two successive crests or two successive troughs. The wavelength is equal
to the distance between centers of two successive compressions or two
successive rarefactions.

Selected problems

1) The figure shows the relation between time (t) in milliseconds and the displacement in Cm to a wave motion.

a) The wavelength ( )

b) Periodic time

c) Frequency

d) Velocity of propagation.

e)Amplitude

f) The distance (ab) represents …… and equals …………. The two point a,b are …….. While the two points a, c are………………..

The given figure shows a relation between the displacement in
cm and the time in seconds for a transverse wave from this figure Find.

a-The frequency. b-The wave length.

c-The amplitude. d- The wave velocity.

1st s 06

The figure shows the relation between the displacement in
centimeter and the time in seconds for a wave, find the value of each
of the following:

a- the wave length

b- the velocity of this wave.