Oxford Revise AQA GCSE Combined Science Foundation | Chapter P11 answers

P11: Waves

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

microwaves

x-rays

1

1

AO1

6.6.2.1

01.2

transverse

1

AO1

6.6.2.1

01.3

energy

1

AO1

6.6.2.1

02.1

\( \rm{frequency} =
\frac{20}{10}
\)

= 2 (Hz)

1

1

AO2

6.6.1.2

02.2

\(\rm{wavelength} =
\frac{0.3}{20}
\)

= 0.015 m

1

1

AO2

6.6.1.2

02.3

speed = frequency × wavelength

1

AO1

6.6.1.2

02.4

speed = 2 × 0.015

= 0.03

m/s

1

1

1

AO2

6.6.1.2

03.1

radio waves – television

microwaves – mobile phones

1

1

AO1

6.6.2.4

03.2

x-rays

to look at broken bones

accept any correct use of medical x-ray imaging

1

1

AO1

6.6.2.4

03.3

skin cancer/premature aging of the skin

1

AO1

6.6.2.3

03.4

sievert

1

AO1

6.6.2.3

04

Example answer:

both waves are used for imaging

our eyes detect visible light

x-rays are used to look inside the body

x-rays have a higher frequency than visible light

x-rays have a shorter wavelength than visible light

large doses of visible light can cause blindness

smaller doses of X-rays can cause cancer

accept reverse statements

6

AO3

6.6.2.1

6.6.2.3

05.1

C above a place where the coils are close together

R above a place where the coils are far apart

1

1

AO2

6.6.1.1

05.2

1.5 m = 3 waves

\(
\frac{1.5}{3}= 0.5\ \rm{m}
\)

1

1

AO2

6.6.1.1

6.6.1.2

05.3

speed = frequency × wavelength

accept v = fλ or correct rearrangements

1

AO1

6.6.1.2

05.4

1.0 m/s = frequency

\(\rm{frequency} =
\frac{1.0}{0.5}
\)

= 2

Hz

1

1

1

AO1

AO2

6.6.1.1

6.6.1.2

05.5

longitudinal

1

AO1

6.6.1.2

06.1

period = the time for one wave in seconds

\(\rm{period} =
\frac{1}{\rm{frequency}}
\)

1

1

AO1

6.6.1.2

06.2

\(\rm{period} =
\frac{1}{500}
\)

= 0.002 (s)

1

1

AO2

6.6.1.2

06.3

500 × 5

= 2500

1

1

AO2

6.6.1.2

06.4

m/s

1

AO1

6.6.1.2

07.1

C

1

AO1

6.6.2.2

07.2

refracted

direction

1

1

AO1

6.6.2.2

07.3

it goes straight through/it does not change direction

1

AO2

6.6.2.2

08.1

Example answers:

any three improvements and reasons from:

1. use an infrared detector instead of the thermometer

because it will be more sensitive/give a more accurate reading/have better resolution

2. use the ruler to make sure the detector is the same distance from each can

so that it is a fair test / it is a control variable

3. use a lid on each can

to ensure the temperature of the water stays the same

4. same surface area of can

so that it is a fair test / it is a control variable

5. surroundings have the same temperature

so that it is a fair test / it is a control variable

one mark for each improvement

one mark for each reason (which must be consistent with the improvement)

6

AO3

6.6.2.2

08.2

B

it (thermometer) has the highest temperature, so is emitting the most infrared radiation

1

1

AO2

6.6.2.2

09.1

visible light has a longer wavelength than ultraviolet radiation

visible light has a lower frequency than ultraviolet radiation

1

1

AO2

6.6.2.1

09.2

(increased risk of) cancer/mutation of genes

1

AO1

6.6.2.3

09.3

frequency

the higher the frequency, the more energy the waves carry

1

1

AO3

6.6.2.1

10.1

zero/0

1

AO2

6.5.4.1.1

10.2

\(\rm{speed} =
\frac{\rm{distance}}{\rm{time}}
\)

1

AO1

6.5.4.1.2

10.3

distance = 4.5 miles × 1609

= 7240.5 m

time = 20 min × 60s

= 1200 s

\(\rm{speed} =
\frac{7240.5}{1200}
\)

= 6.0 m/s

1

1

1

1

AO1

AO2

6.5.4.1.2

10.4

the speed varies over the journey/the calculation assumes the speed is constant

1

AO3

6.5.4.1.2

10.5

there is a force of friction/air resistance/resultant force is zero

Newton’s first law

says that an object moves with a steady speed when the resultant force is zero/the forces cancel out

1

1

1

AO3

6.5.4.2.1

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