PROGRAM DIDIK CEMERLANG AKADEMIK

SPM

ORGANISED BY:

JABATAN PELAJARAN NEGERI PULAU PINANG

PHYSICSMODULE

1.0 WAVES

TOPIC:1.0 WAVES

1.7 ELECTROMAGNETIC WAVES

CONTENTS:

1. CHAPTER HIGHLIGHT (30 MINUTES)

2. ACTIVITY (50 MINUTES)

3. ASSESSMENT (40 MINUTES)

4. MARKING SCHEME(ANSWER KEY)

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CONTENT : ELECTROMAGNETIC SPECTRUMCHAPTER HIGHLIGHTS ( 30 MINUTES)

1. Electromagnetic spectrum The distribution of all the different types of electromagnetic waves arranged in ascending order of wave lengths or frequencies.

2. Common Properties Of All Electromagnetic Waves.

Common properties of electromagnetic wavesCommon properties of electromagnetic waves

1.Transverse waves1.Transverse waves

2.Travel at the same speed of 3 x 108 ms-1 in vacuum but slow down in other material media.

2.Travel at the same speed of 3 x 108 ms-1 in vacuum but slow down in other material media.

3. Travel through solids, liquids, gases and vacuum.

3. Travel through solids, liquids, gases and vacuum.

4. Obey the laws of reflection,refraction,diffraction and interference.

4. Obey the laws of reflection,refraction,diffraction and interference.

5. Can be absorbed and emitted by matter.5. Can be absorbed and emitted by matter.

6. The wave equation , v = f6. The wave equation , v = f

7.Transfer energy from one place to one anotherwithout the need for a material medium.

7.Transfer energy from one place to one anotherwithout the need for a material medium.

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Types of EM waves

Source Application Danger/over exposure

Radio wave Transmitter Communication Transmitting TV radio programmes

Large doses of radio wave may cause cancer and leukemia.

Microwave Microwave transmitter

Communicate with satellite.

Heating food in microwave oven

Telephony

Burns if concentratedAffects the brainCataracts

Infrared SunHot objects

Remote control Security system Thermal imaging

Burns if concentrated

Visible light SunHot objectsFlame

Seeing Photography Photosynthesis

Very intense visible light can damage the retina

Ultraviolet rays SunSpecial lamp

Kill microbes Detect security codes

on expensive equipment

SunburnSkin cancerCataracts

X - rays X- rays machine

Imaging defects in bones

Security system

Destroy body cellsCause mutation Cancer

Gamma rays Radioactive nuclei decaying

Kill cancer cells Radiotheraphy Sterilisation Medical tracers

Destroy body cellsCause mutations Cancer

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ACTIVITIES (50 minutes)

1. The diagram shows an electromagnetic spectrum

The waves at P,Q,R and S are

P Q R S

A. ultraviolet x-ray microwave infraredB. x-ray ultraviolet infrared microwaveC. microwave infrared ultraviolet x-rayD. x-ray infrared ultraviolet microwave

2. At an airport, a passenger’s bag is placed in the baggage scanner.

The contents in the bag are examined by using

A. x-rayB. gamma raysC. ultraviolet raysD. infrared rays

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3.All electromagnetic waves have the sameA. speed in vacuoB. speed in given mediumC. frequency in vacuoD. frequency in a given medium

4.Which of the following lists of electromagnetic radiation is arranged in order of increasing length?

A. ultraviolet, visible light, infrared, radio wavesB. infrared, ultraviolet, visible light, radio wavesC. ultraviolet, visible light, radio waves, infrared D infrared, radio waves, ultraviolet, visible light

5. Arrange the following electromagnetic waves in the order of decreasing wavelength

Ultraviolet x- ray red light violet light microwaves infrared

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6. Name three of the sources of electromagnetic waves.

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7. Name one property that all electromagnetic waves have in common.

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8. State one application for each type of the following electromagnetic waves .

(a) gamma rays: ________________________________________________

(b) ultraviolet rays :______________________________________________

(c) infrared rays : _______________________________________________

(d) radio waves:_________________________________________________

(e) x –rays : ____________________________________________________

(f) visible light: ________________________________________________

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(g) microwaves:________________________________________________

9. Name the electromagnetic waves which are used widely in the field of

(a) communication

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(b) medicine

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10(a) Which component of the electromagnetic spectrum is detrimental to us if exposed excessively?

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(b)For each type of electromagnetic waves mentioned in (a), state the detrimental effects concerned.

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ASSESEMENT ( 40 minutes)1. The diagram below shows some of the components of the electromagnetic

spectrum.

radio waves

microwaves

infrared A ultraviolet x-rays gamma rays

(a) What is the name of component A?

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(b) What is the speed , in vacuum, of radio waves and ultraviolet waves?

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(c) All the electromagnetic waves are transverse. What is the meaning of transverse?

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2. (a) Figure 1 shows the main components of electromagnetic spectrum in order of increasing frequency.

radio A visible B x-rays C

Increasing frequency

Figure 1

What are the names of the missing components marked A to C?

A: __________________

B: __________________

C: __________________

(b)Figure 2 shows the seven components of visible light which is part of the electromagnetic spectrum

violet indigo X Y Z orange red

Figure 2

Identify the missing components X, Y and Z.

X: ____________________

Y : ____________________

Z: _____________________

(d) State two common characteristics of all electromagnetic waves when they travel from the Sun to Earth.

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3. The following are types of waves

Infrared ocean waves radio

Sound ultraviolet

(a) Which of these waves are in the electromagnetic spectrum?

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(b) State one property of all electromagnetic waves

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4.Figure (a) shows an airport radar transmitting microwave signals. Microwaves are transmitted to determine the position of aeroplanes.

(a) microwaves are a type of ___________________ waves.

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(b) The radar transmit a signal at a velocity of 3.0 x 10 8 ms-1 towards the aeroplane P and detects the reflected signal 4.0 x 10 -4 s later.

Calculate the distance of P from the radar transmitter at that time.

(c)The radar detects the same signal after reflection by another aeroplane,Q. The signal from Q arrives later than the signal from P. (i)Compare the distances of P and Q from the radar.

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(ii)State how the difference of distance of P and Q from the radar is determined at any time.

________________________________________________________________

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Answers of ACTIVITIES1. B2. A3. A4. A 5.microwaves, infrared, red light, violet light, ultraviolet, x-ray6.sun, lighted bulb, fire7.transferring of energy from the source to its surrounding area8(a)food sterilization (b)scanning body(in medicine) (c)kill bacteria (d)to light up dark places (e)remote control (f)telecommunication (g)broadcasting9.(a)microwaves, radio waves

(b)gamma rays, x-rays10.(a)gamma rays, x-rays, ultraviolet (b)gamma rays : cause cancer

X rays : cause cell dangerUltraviolet : cause skin cancer

Answers of ASSESMENT1.(a) visible light (b)3 x 10 8 ms-1

(c)Transverse waves mean that the waves travel in a direction perpendicular to the direction of vibration.

2.(a) A : infrared B : ultraviolet C : gamma rays

(b) X : blue Y: green Z : yellow (c)1. They can travel through in vacuo 2. They obeys the laws of refraction, reflection, diffraction and interference3. (a) radio, infrared and ultraviolet (b) All electromagnetic waves travel with the same speed of 3 x 10 8 ms-1

4.(a) electromagnetic waves

(b) V =

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V =

= 60000 m

(c)The distance of Q is greater than the distance of P from the radar

(c) Determine the shortest distance of P or Q to the radar i.e the distance of P to the radar is equal as Q to the radar.

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