MYP-YEAR: 5

GLOBAL CONTEXT: Globalisation and sustainability

Revision Sheet

Name: Date:

Criterion A: Knowing and understanding

Q1. (I) While performing an experiment an MYP 5 student established the following circuit, he wants to
use Ohm’s law and basic circuitry principles to evaluate various aspects of this circuitry.

a. If R1=3Ω, R2= 6Ω, R3 and R4 are 5Ω each, apply Ohm’s law and circuit concepts to find the total
current flowing through the circuit, if the total voltage supplied by the batteries is 20 V. [4]
b. Student accidentally touches one of the resistors and finds it hot. Describe, the factors and their
relationship with heat energy produced that could have given rise to this heat energy? [4]

(ii) In a birthday party a balloon fell from the wall, Ritu picked up the balloon and rubbed it against her dry
hairs and put it back on the wall, surprisingly balloon stuck to the wall, explain the electrostatic
phenomenon involved that made the balloon cling to the wall. [4]

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 Image credits: http://smallscience.club/experiments/hair-raising-electric-balloon/

(iii) Justify the validity of the statement, “ It is advantageous to connect the household electrical appliances in
parallel” [2]
(iv) The meter reading given below is the consumption of electricity in 1 day ( 24 hrs) at your
house . Comment on your power consumption if 1 unit of electricity cost Rs 10. [4]

(Image credits: https://www.npower.com/help-and-support/meter-readings/how-to-read-an-electricity-meter/)

Q2. Some birds migrate every autumn, some fly to cooler countries and some fly to warmer countries. The
bar-tailed godwit in the photograph can fly for nearly 11,000 km without stopping. During the eight-day
journey that it takes to cover that distance, the bird doesn’t stop for food or rest. This makes the bar-tailed
godwit the bird with the longest recorded non-stop flight.

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(Image credits: https://www.smithsonianmag.com/smart-news/bird-designed-jet-fighter-sets-new-record-
longest-nonstop-bird-migration-180976078/)
i. One bar-tailed godwit flies 1200 km in a day. Calculate the speed in km/h. [1]
ii. Scientists fit satellite transmitters to 16 godwits at two locations in New Zealand. Later the scientists
use the information from the satellite transmitters and calculate that average speed of the bird is 56
km/h. Outline two factors that may affect the average speed achieved by the bar-tailed godwit. [2]
iii. The graph below shows part of a different migratory bird’s journey. Explain what is happening with
respect to the force, velocity and acceleration of the bird between points C and D on the graph.
Include in your explanation which of Newton’s law is being obeyed as the graph changes. [4]

iv. Use the graph to calculate the distance travelled by the bird while decelerating. [3]
Q3. Infrasound is a low frequency longitudinal wave that elephants, whales, rhinoceros and alligators use to
communicate with each other. The frequency of infrasound waves is lower than 20 Hz. Infrasound wavs can
travel very long distances through air at a speed of 330 m/s.

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 i. Calculate the frequency of wave A. [2]
ii. Identify which two waves have the same frequency. [1]
iii. Calculate the wavelength of wave C. [2]
iv. Infrasound waves have a frequency of less than 20 Hz. Use your answers above to identify
which wave does not show infrasound. [1]

Criterion D: Reflecting on the impacts of sciences

Q4. This question is about generation and transmission of electricity. In many developed countries,
electricity is generated in large power stations, far away from where the people who use electricity love
and work.

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The energy sources that power the generators in large industrial countries are coal, gas and nuclear
(fission) reactors, or a mix of these.
i. Suggest two reasons why people would not want a coal-fired power station in or near their city. [2]

ii. Outline a reason why coal-fired and nuclear power stations are built near large rivers or the sea. [1]

iii. The cables lose some electrical power as it transfers from the power station to the city. One solution is
to reduce this power loss by increasing this power loss by increasing the voltage of the electricity in the
cables when the energy travels long distance.

a) If P = VI, when the secondary voltage doubles, state what happens to the secondary current. [1]

b) Describe why increasing the voltage reduces the power lost during transmission. [3]

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 c) Coal is a source of energy that is found in many parts of the world. When coal is burned, it produces three
gases: water vapor (H2O), carbon dioxide (CO2) and sulfur dioxide (SO2).
Select any two gases listed above and describe a problem associated with each. [4]

d) Large power stations operate continuously, 24 hours a day, and it often takes many days to tun them on and
off. Suggest why a power generation company might sell electricity more cheaply at night than during a day.
[3]

Q5. Source:

Researchers are developing tools to substantially reduce the operations and

maintenance costs of wind farms. The novel tools will be tested on three European
wind farms in 2020.

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The EU has set an ambitious goal to become a world leader in renewable energy.
Given that this is a relatively young industry, renewable sources aren't exploited as
efficiently as they could be in the future, given time and experience. However, there
is progress in the sector. For example, offshore wind energy is becoming more and
more competitive and is gaining importance as a part of the power system.

One of the main obstacles in the use of offshore wind energy is the high cost
involved in operations and maintenance (O&M). O&M costs make up a big share of
the total cost of a wind turbine, often totalling around 30 % of its total life-cycle cost.
To boost wind energy in Europe, offshore wind farms need to become more
efficient, a problem that the EU-funded project ROMEO is tackling head-on.

ROMEO is developing useful tools that will allow wind farm operators to improve
their decision-making processes and shift from corrective, calendar-based to less
costly condition-based maintenance strategies. Its advanced monitoring systems
will be able to detect key failures in major components of wind turbines. Models are
also being developed to diagnose and predict failures in existing turbines, thus
minimising downtime. An interoperable cloud-based and Internet of things platform
will be providing an advanced analytics system for such diagnosis and prognosis
models to better understand how turbine components behave in real time.
Operators will therefore be able to maximise the turbines' lifespan and minimise
O&M costs.

Pilot tests at German and UK wind farms

The newly developed technology will be tested on three European offshore wind
farms next year. The pilot phase test site located in the German waters of the Baltic
Sea has a power capacity of 350 MW generated by 70 turbines. The two UK-based
facilities are a 27-turbine 62-MW-capacity farm off the North Yorkshire coast and a
108-turbine 714-MW farm off the east coast of East Anglia, both in the North Sea.

"The models and tools that we are developing will be tested … from mid-2020"
reported Cesar Yanes of project coordinator Iberdrola Renovables Energía in a
news item published in the 'Offshore Wind Journal'. "The pilot projects will show us
how successful we have been and will enable us to test technology that will monitor
turbine components such as the gearbox main bearing and transformer and the
substructure of a turbine."

Yanes added that by testing their system on different wind farms with dissimilar
turbines and environmental conditions, they will be able to prove that their
technology can be transferred to other offshore and onshore projects. This, he
explained, "will be required if our overall goal of reducing the cost of wind energy is

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to be met. Our aim is to reduce the incidence of component failure and unplanned
maintenance while increasing reliability."

ROMEO (Reliable OM decision tools and strategies for high LCoE reduction on
Offshore wind) is harnessing the wide-ranging expertise of its 12 project partners,
including turbine component manufacturers, service providers, wind farm operators
and IT market leaders. The pilot phase of ROMEO is expected to last until the end
of the project in 2022.

Discuss and evaluate [15]

i. Advantages and disadvantages of wind farms.
ii. Environmental and Economic impacts.
iii. Concluding appraisal

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