physics form 5 wave (1)

8/12/2019 physics form 5 wave (1)

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JPN Pahang

Physics Module Form 5

Teachers Guide Chapter 6:Wae

CHAPTER 6: WAVE

6.1 Understanding Waves

1. Motion of Waves

A wave front is a line or plane on which the vibrations of every point on it are in phase and areat the (same/different) position from the source of the water.

2. When we use a fingertip to touch the surface of water repeatedly (circular/plane) wave fronts

are produced.

!. "ypes of waves

"here are 2 types of waves#$

(a) %%%%%%%%%%%%%. (b) %%%%%%%%%%%%%.

&. "ransverse wave(i) "ransverse wave is a wave in which the vibration of particles in the medium is at

(parallel/perpendicular) to the direction of propagation of the wave.

A A

' '

A (crest / compression)' (rarefaction /trough)

(ii). *ample of transverse wave#

i. %%%%%%%%%%%%%%..

ii%%%%%%%%%%%%%%...

iii%%%%%%%%%%%%%%..

+. ,ongitudinal waves


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(i) A longitudinal is a wave in

which the vibration of particles

in the medium is (parallel /

proportional) to the direction of

propagation of wave.

-

-

(ii) *ample of longitudinal wave# %%%%%%%%%%%%%

- (crest / compression)

(rarefaction / troug


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Amplitude, Period and re!uen"# o$ a Wave

1. uilibrium position is

%%%%%%%%%%%%%%%%%%%%

%%%.

2. 0ne complete oscillation of the pendulum occurs

when the pendulum bob moves from

%%%%%%%%%%%%%.

!. "he period " of a vibrating system is

%%%%%%%%%%%%%%%%%...

&. reuency f is

%%%%%%%%%%%%%%%%%%%%

"he 3 unit is%%%%%%.

+. troboscope is use to

%%%%

%%%%

%%%%

%%%%

%

troboscope freuency number of slits * rotation freuency

of stroboscope

4. Wave speed

3f the wavelength of the wave is 5 the waves

move forwards a distance of!* 5 per second.

"herefore the speed of waves

v % $ &


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'

'


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E

(e

r

"

i

s

e

6

.

1

1. (a)

"h

e

wa

vel

en

gth

of

the

wa

ve

in

the

dia

gra

mab

ov

e is

giv

en

by

lett

er

%

%


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%.

(b)

"he

amplit

ude of

the

wave

in the

diagra

m

above

is

given

by

letter

%%%

%

2. 3ndicat

e

the

int

erv

al

wh

ich

rep

res

ent

s

on

e

full

wa

vel

en

gth

.


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A

n

s

w

e

r

#

%

%

%

%

%

%

%

.

.

E

(

e

r

"

i

s

e

6

.

1

1

1. 3n

a

n

e

*

p

er

i

m

e

nt

,i

m

o

bs

er

v


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es

th

at

a

si

m

pl

e

p

e

n

d

ul

u

m

c

o

m

plet

es

!

6

os

ci

ll

at

io

ns

in

1

+.

6

se

c

o

n

ds

.

Wh

at

is

(a) the

freu

ency

of

oscill

ation

7


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(b) the

perio

d of

oscil

latio

n7

"ns#er:

2.


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8alculate the freuency of the given wave above.

!. 'ased in the displacement$distance graph

of a wave find

(a) the amplitude

(b) the wavelength of the wave

"ns#er:

&. A transverse wave is found to have a

distance of & cm from a trough to a crest a

freuency of 12 9: and a distance of + cm

from a crest to the nearest trough.

;etermine the amplitude period

wavelength and speed of such a wave.

"ns#er:

+. A girl moves a long slin


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"ns#er:


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)

&.+ cm

=. "he figure shows a wave front pattern ina ripple tan< produced by a vibrating

dipper at freuency of + 9:. What is the

wave speed7

"ns#er:

26 cm

>. A mechanical stroboscope has 12 slits and

rotates at a freuency + 9:. "he stroboscope

is used to observe water waves. "he observer

notes there are 4 successive bright bands at a

distance 26 cm. 8alculate the speed of the

water waves."ns#er:

?. "he figure shows a loudspea


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A given wave travels at a speed of 2 * 16+ms$1. 3f the

freuency of the wave is 1666 9: 8alculate the

wavelength

"n

s

#

e

r

:

11. (a) 'ase on the figure determine

(i) the amplitude

(ii) the wave length

(b) What is the freuency of the sound if the

speed of sound is !!6 ms $1.

"ns#er:


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*amping

1. ;amping is a

%%%%%%%%%%%%%%%%%%

%%%%%%%%%%..

2. When a system is damped the amplitude of

the of oscillation %%%%%.

( decreases / increases ) slowly until the


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system stops oscillating.

3. ;amping is usually caused by #$

i. %%%%%%%%%%%%%%

%%%%%%%%

ii. %%%%%%%%%%%%%%

%%%%%%%%

Resonan"e

A resonance is

%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%.

E(periment to s+o a p+enomenon o$ resonan"e

A

'

;

8

igure 4.12# 'arton@s

pendulum

-endulum ' and ; are the same length. When

pendulum ' oscillates all the pendulum start

; have the same length so there have same

naturalfreuency. o pendulum ; will oscillate with

%%%%%% (ma*imum/minimum) amplitude


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6.- AA/023 RER/ECT24 4 WAVE

1. eflection of a wave occurs

when a wave stri


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water waves

(a) (b)

2. how the dar< and bright pattern on the

screen below.

Water waves

Ripple tank

Screen

Re$le"tion o$ /ig+t Wave

1. When rays of light stri


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%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%

%%%%%

%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%

%%%%...

2. "he bright and dar< bands of the wave

pattern formed on the screen because

the surface of water acts as lenses. "he

crest of water waves similar with

%%%%%%%%% $concae lens

%cone& lens' and the trough of water

waves similar with

%%%%%%%%% $concae lens

%cone& lens'(

E(er"ise 6.-1

"he diagram shows a single ray of light

being directed at a plane mirror. What

are the angles of incidence and

reflection7

(a)

(b)

i r

Re$le"tion o$ sound aves

1. "he sound waves are reflected by walls

and ceilings of buildings unborn baby or

sea bed.


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2. "he sound wave from the stopwatch

e*periences a reflection after stri


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2. 3f an echo is heard one second

after the holler and reflects off

canyon walls which are a

distance of 1=6 meters away

then what is the speed of the

wave7

6.5 AA/023 RERACT24 4 WAVE

1. "he refraction of water waves occur when thereis a%%%%%%%%%%%%%%%%%%%%


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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

2. After refraction the wave has the same%%%%%%%%%%. but a different%%%%%%%%

Re$ra"tion o$ Water Waves

51 52

;eep hallow

1. When the water wave travel from a deep area the

direction of the waves is refracted

%%%%%%%.

$to#ards% a#ay !rom' the normal.

2. "he angle of incidence iof the water

is %%%%%%.(greater % smaller'

than the angle of refraction r

!. When the refraction of a wavehappened the freuency f does not

change but the

%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%the

wave change.

E(er"ise 6.5

1. 8omplete the table below to show theproperties of refracted water waves when wave


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travels from one area to another area of a

different depth. Dse the words given.

Properties o$ re$ra"ted ater

aves

*eep ater to s+allo ater allo ater to deep ater

Wavelength decreases/ increases/ unchanged decreases/ increases/ unchanged

Eelocity decreases/ increases/ unchanged decreases/ increases/ unchanged

reuency decreases/ increases/ unchanged decreases/ increases/ unchanged

;irection of travel 'ends toward/ away from normal 'ends toward/ away from normal

2. 0n each of the following diagram draw therefracted wave by the perspe*.


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3. A plane wave has a wavelength of 2 cm anda velocity of > cm s$1as it moves over thesurface of shallow water. When the planewave moves into an area of greater depthits velocity becomes 12 cms$1. What is the

a. Wavelength

reuency of the wave in the

area of greater depth7


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Re$ra"tion o$ ater ave o$ t+e sea ater

1. Why are the speed and wavelength of waves in the middle of the sea almost uniform7

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

2. What do you thin< would happen to the wave speed if the depth of water is increased7%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%.

.

!. Why do the distances between the wave fronts decrease as the waves approach the beach7

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%

&. Why the water in the bay is stationary compared to the water at the cape7

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Re$ra"tion o$ /ig+t Waves

1. When a ray propagates from one medium to an optically denser medium the ray refracts

)))))))))) $to#ards % a#ay !rom) the normal.

2. "he speed of light )))))($decreases%increases'as it propagates in the glass

bloc


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Re$ra"tion o$ ound Waves

1. ound waves travel faster in warm air than in %%%%... (cold/hot) air.

2. 0n a hot day the hot surface of the arth causes the layer of air near the surface to be

%%%%%%. $#armer%cooler'

!. "his causes sound waves to be %%%%%%.. $re!lected%re!racted' away from the

arth.

&. 0n a cool night the sound waves travel %%%%%%.(slo#er%!aster)in the cooler

layer of air near the surface of the arth than in the upper warmer air. "he waves are

refracted towards the arth. 9ence sound can be heard over a longer distance on a cold

))))))))$night%day'compared with a hot day.

physics form 5 wave (1)

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