(a) A train is powered by a diesel engine - Edexcel - GCSE Physics - Question 2 - 2013 - Paper 1
Question 2
(a) A train is powered by a diesel engine.
The diesel engine is used to turn a generator.
The generator provides electricity for electric motors which drive the whee... show full transcript
Worked Solution & Example Answer:(a) A train is powered by a diesel engine - Edexcel - GCSE Physics - Question 2 - 2013 - Paper 1
Step 1
Draw one straight line from each train part to its useful energy transfer.
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Answer
Diesel Engine --> Chemical to Electrical
Generator --> Electrical to Kinetic
Motor --> Kinetic to Chemical
Motor --> Kinetic to Electrical
Step 2
Calculate the amount of energy wasted in one second in the generator.
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Answer
Energy wasted can be calculated using the formula:
Energy wasted=Energy supplied−Useful energy
Substituting the known values:
Energy wasted=1400 kJ−1300 kJ=100 kJ
Step 3
Calculate the efficiency of the generator.
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Answer
The efficiency can be calculated using the formula:
Efficiency=(Energy suppliedUseful energy)×100
Substituting the known values:
Efficiency=(14001300)×100=93%
Step 4
Suggest why the motors are painted black.
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Answer
The motors are painted black because black is a good thermal radiator, helping to remove wasted energy or heat from the motors, thus preventing them from overheating.
