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Question 18M.2.SL.TZ2.a.iii

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Date May 2018 Marks available [Maximum mark: 1] Reference code 18M.2.SL.TZ2.a.iii
Level SL Paper 2 Time zone TZ2
Command term Determine Question number a.iii Adapted from N/A
a.iii.
[Maximum mark: 1]
18M.2.SL.TZ2.a.iii

In a pumped storage hydroelectric system, water is stored in a dam of depth 34 m.

M18/4/PHYSI/SP2/ENG/TZ2/05

The water leaving the upper lake descends a vertical distance of 110 m and turns the turbine of a generator before exiting into the lower lake.

Water flows out of the upper lake at a rate of 1.2 × 105 m3 per minute. The density of water is 1.0 × 103 kg m–3.

The storage system produces 1.8 GW of electrical power. Determine the overall efficiency of the storage system.

[1]

Markscheme

efficiency is « 1.8 2.5 =» 0.72 / 72%

[1 mark]