CAIE IGCSE Physics 3.3 Electromagnetic Spectrum Topic Practice

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Covered syllabus points

3.3.1—Main regions of the EM spectrum in3.3.2—All EM waves travel at the same high3.3.3—EM spectrum uses: (a) radio waves3.3.4—Harm from excessive EM radiation: (a)3.3.5—Communication with artificial3.3.6—Speed of EM waves in a vacuum is 3.0 ×3.3.7—EM radiation: (a) mobile3.3.8—Difference between a digital and3.3.9—A sound can be transmitted as a3.3.10—Benefits of digital signalling

Question 1

[Maximum number: 1]

The table gives the wavelengths of three electromagnetic waves.

electromagnetic<br>wavewavelength /m/ \mathrm{m}
P3.2×10−33.2 \times 10^{-3}
Q5.0×10−95.0 \times 10^{-9}
R2.6×1032.6 \times 10^{3}

Which row correctly identifies P, Q and R ?

P

Q

R

microwave

radio wave

X-ray

microwave

X-ray

radio wave

radio wave

microwave

X-ray

radio wave

X-ray

microwave

Question 2

[Maximum number: 6]

Some of the components of the electromagnetic spectrum, in order of decreasing wavelength, are shown.
radio waves
microwaves
visible light
ultraviolet radiation
gamma rays

Question (a)

(a)

State the speed at which all electromagnetic waves travel in a vacuum.

[ 1 ]

Question (b)

(b)

State which of the components of the electromagnetic spectrum shown has the lowest frequency.

[ 1 ]

Question (c)

(c)

Two components of the electromagnetic spectrum are not listed above.

State the names of these components.
1.
2.

[ 2 ]

Question (d)

(d)

One application of microwaves is in microwave ovens, which cook food very quickly.

Fig. 7.1 shows the inside of the glass door of a microwave oven, covered with a metal mesh.

Fig. 7.1

Fig. 7.1

The metal mesh prevents the microwaves from escaping by reflecting them back into the oven.

[ 2 ]

Question (i)

(i)

Suggest one reason why it is sensible to prevent microwaves from escaping.

[ 1 ]

Question (ii)

(ii)

State one further application of microwaves, other than in microwave ovens.

[ 1 ]

Question 3

[Maximum number: 4]

Question (a)

(a)

Table 5.1 shows applications of regions of the electromagnetic spectrum.
Complete the second column of the table with the region of the electromagnetic spectrum used for each application.

Choose from the regions in this list:
gamma rays infrared microwaves radio waves ultraviolet
Each region may be used once, more than once or not at all.

Table 5.1

Table 5.1

[ 3 ]

Question (b)

(b)

State the approximate speed of radio waves in air.

speed =...........................................................

[1]

[ 1 ]

Question 4

[Maximum number: 1]

Some of the components of the electromagnetic spectrum, in order of decreasing wavelength, are shown.
radio waves
microwaves
visible light
ultraviolet radiation
gamma rays

State the speed at which all electromagnetic waves travel in a vacuum.

Question 5

[Maximum number: 3]

Table 5.1 shows applications of regions of the electromagnetic spectrum.
Complete the second column of the table with the region of the electromagnetic spectrum used for each application.

Choose from the regions in this list:
gamma rays infrared microwaves radio waves ultraviolet
Each region may be used once, more than once or not at all.

Table 5.1

Table 5.1

Question 6

[Maximum number: 1]

X-rays are electromagnetic waves. Fig. 6.1 shows the position of X-rays in the electromagnetic spectrum arranged according to increasing wavelength.

Fig. 6.1

Fig. 6.1

State one reason why it is necessary to take safety precautions when X -rays are used.
[Total: 10]

Question 7

[Maximum number: 1]

Which part of the electromagnetic spectrum is used to send television signals from a satellite to Earth?

A

infra-red

B

microwaves

C

ultraviolet

D

visible light

Question 8

[Maximum number: 1]

Fig. 8.1 shows images produced during two different medical scanning procedures.

Fig. 8.1

Fig. 8.1

X-rays are part of the electromagnetic spectrum.

State the speed of X-rays in a vacuum.

Question 9

[Maximum number: 1]

Fig. 7.1 shows some uses of electromagnetic radiation and different regions of the electromagnetic spectrum.

Fig. 7.1

Fig. 7.1

A Bluetooth headset can be used to listen to music on a mobile (cell) phone without the need for wires to connect the headset to the phone.

Suggest why a Bluetooth headset only works well over short distances.

Question 10

[Maximum number: 3]

A mobile phone (cell phone) network uses microwaves of frequency 1.9×109 Hz1.9 \times 10^{9} \mathrm{~Hz} to transmit and receive signals.

The speed of microwaves in air is 3.0×108 m/s3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}.

All mobile phone (cell phone) networks use digital signals to communicate with the phone.

Describe, with the aid of a diagram, how a digital signal differs from an analogue signal.

Question 11

[Maximum number: 2]

A mobile phone (cell phone) network uses microwaves of frequency 1.9×109 Hz1.9 \times 10^{9} \mathrm{~Hz} to transmit and receive signals.

The speed of microwaves in air is 3.0×108 m/s3.0 \times 10^{8} \mathrm{~m} / \mathrm{s}.

All mobile phone (cell phone) networks use digital signals to communicate with the phone.

State two advantages of using digital signals rather than analogue signals.

1

2

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