I- Complete the following statements: (troughs - frequency - compressions - along - propagates - crests - rarefactions - perpendicular - wave length - disturbance)

Chapter One: Wave Motion

I- Complete the following statements: (troughs - frequency - compressions - along - propagates - crests - rarefactions - perpendicular - wave length - disturbance) 1- The product of...... x..... = the wave velocity. 1- frequency - wavelength

2- In a transverse wave, the direction, of vibration of the medium's particles, is.... to the direction of the wave propagation, while in longitudinal waves, the direction of vibration of the medium's particles is..... the direction of propagation. 2- perpendicular - along

3- A wave motion is a..... that..... and carries energy along. 3- disturbance - propagates.

4- Longitudinal wave consists of..... &..... 4- compressions - rarefactions

5- Transverse wave consists of..... &..... 5- crests - troughs

- Complete the following statements:- (disturbance - A - period - frequency - two - propagation of disturbance - momentum - medium - troughs - meters - crests - - two - T - - rarefactions - wavelength - amplitude - compressions). 6- The production of a mechanical wave needs.....,..... &..... - disturbance - medium - propagation of disturbance

7- The max. displacement for a vibrating body is called....., denoted as..... - amplitude - A

8- The time taken by a continuously vibrating body to complete one oscillation is called...... denoted as..... - period - T

9- The Number of complete oscillations per sec. is called..... denoted as..... - frequence -

10- The relation that relates the frequencey of a wave motion to its periodic time is..... - or

11- Transverse waves..... propagate in air because the intermolecular forces are very..... - can't - weak

12- The wave length of a transverse wave is the distance between..... successive..... or....., while in longtudinal waves it is the distance between..... successive..... or..... - two - crests - troughs - two - compressions - rarefactions

II- Put () or () infront of the following statements:- 1- Sound waves can propagate through vacuum. 1- ()

2- The wave length of a longtudinal wave is the distance between two successive points having the same phase. 2- ()

3- The displacement of a vibrating body is the distance between the position of body at a given instant and its position where the velocity is max. 3- ()

4- A vibrational motion may consist of one or more simple harmonic motions. 4- ()

5- In solids, propagation of transverse waves is faster than the propagation of longitudinal waves. 5- ()

6- Both transverse & longitudinal waves can propagate at the water's surface, but the longitudinal waves are most common. 6- ()

7- In longitudinal waves the regions where the particles of medium are apart is called 'compressions'. 7- ()

8- The amplitude is the max. displacement. 8- ()

9- For all wave motions () 9- ()

10- The oscillation of a simple pendulum could be considered a simple harmonic motion. 10- ()

11- In the shown simple pendulum the displacement 'X' could be calculated from: . Where: 'L' is the length of pendulum ' ' the angle it makes with the rest position. 11-

III- what is meant by each of the following:- 1- The wavelength of a longtudinal wave is 15 cm? 1- This means that: the distance between two successive compressions or rarefactions is 15 cm.

2- The frequency of a vibrating string is 500 Hz? 2- This means that: the number of complete oscillations made in one sec. is 500.

3- The amplitude of a vibrating string is 7 cm? 3- This means that: the max. displacement of this string is 7 cm

4- Sound waves are longitudinal waves? 4- This means that: sound waves consist of compressions and rarefactions and the particles of the medium vibrates in the same direction of propagation of the wave.

5- Radio waves are electromagnetic waves? 5- This means that: radio waves consist of electric and magnetic fields.

IV. Give reasons for the following:- 1- Light and radio waves can propagate through vacuum. 1- Because both light & radio waves are electromagnetic waves.

2- For all wave motions, the product: 2- Because .

3- Transverse waves can't propagate through air. 3- Because air molecules are so apart and the intermolecular forces are very weak.

V. State the scientific terms of the following:- 1- The disturbance that propagates and carries energy along. 1- Wave motion.

2- The wave in which the vibrations are perpendicular to the direction of propagation. 2- Transverse wave.

3- The wave in which the vibrations are along the direction of propagation. 3- Longtudinal wave.

4- The distance between two successive crests or troughs. 4- The wavelength of a transverse wave.

5- The distance between two successive compressions or rarefactions. 5- The wavelength of a longtudinal wave.

6- The distance between the position of a vibrating body and its position of rest. 6- Displacement.

7- Tha max. displacement of a vibrating body. 7- Amplitude.

8- The motion of a vibrating body through the time interval as it passes by given point two successive times in the same direction. 8- A complete oscillation.

9- The time taken to pass by a fixed point two successive times in the same direction. 9- Periodic time (period).

10- The Number of complete vibrations per one second. 10- Frequency.

11- The region in longtudinal wave where the molecules are very compact. 11- The compression.

12- The point in transverse wave with max. displacement in positive direction. 12- The crest.

VI- Choose the correct answers between brackets: 1- If the distance between two successive points having the same phase and direction equals 50 cm, then the wave length for such wave equals. (25 cm, 50 cm, 100 cm) 1- 50 cm.

2- In a longtudinal wave the direction of vibrations of the medium particles relative to the direction of propagation of the waves. (in the same direction - in a perpendicular direction - inclined with an angle 45 ْ). 2- in the same direction

3- In longitudinal waves, the points where the molecules of medium are very compact are called...... (compressions - crests - troughs - rarefactions) 3- Compressions.

4- In longitudinal waves, the points where the molecules of medium are very apart are called...... (compressions - crests - troughs - rarefactions) 4- Rarefactions.

5- In transverse waves, the points of max. displacement in the +ve direction are called........... (compressions - crests - troughs - rarefactions) 5- Crests.

6- In transverse waves, the points of max. displacement in the -ve directions are called. (compressions - crests - troughs - rarefactions) 6- Troughs.

VIII. Problems 1-A radar station emits its signal to a satellite just above it at a height of 400 km. This signal was received by another station 300 km away after 3 milli-seconds. Calculate the speed of signal neglecting the time taken by satellite to compute the signal. 1- From fig. the distance The distance traveled by signal = 400 + 500 = 900 km. c= Dist. /t.

2- Using the following table find: a- The colour of a light ray of frequency b- The frequency of the average wavelength emitted by a red-hot iron needle. 2- a)

3- A stationary train produces a whistle of frequency 2000 Hz. The whistle was detected after 3.125 sec. at a distance of 1 km. Find: a- The wavelength of the emitted whistle. b-The number of waves in the distance between the train and sound detector.

4- Find the ratio between the wavelengths of two sound tones of frequencies 512 & 620 Hz travel in the same medium. 4- The two waves travel in the same medium. the velocity is constant

5- A person stands in seawater is passed by 12 sea waves in one minute. Find the frequencey and period of the sea waves.

6. Find the frequency of the voice of a baby, given that it travels 12.8 m in 0.04 sec. and this distance contains 25 waves.

7- Find the number of waves in the distance separating two buildings 300 m apart if a sound wave, of frequency 1000 Hz, travels this distance in one second.

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