A geothermal field requires a combination of which three of the following conditions?

1.A natural underground source of water

2.A mountain in the vicinity

3.An impermeable layer

4.A coal mine in the vicinity

5.A large mass of hot rock in the vicinity

A1, 3 & 5 only ✓ Correct

B1, 3 & 4 only

C2, 3 & 4 only

D2, 4 & 5 only

Correct answer: (A) 1, 3 & 5 only

Explanation

A geothermal field requires a natural underground water source, an impermeable cap layer, and a large mass of hot rock nearby.

Statement 1 holds, as underground water is heated into steam that drives turbines.

Statement 3 holds, since an impermeable layer traps the heat and pressure below.

Statement 5 holds, because a large hot rock mass supplies the heat that warms the water.

Statement 2 fails, as a nearby mountain is not a requirement for geothermal heat.

Statement 4 fails, since a coal mine has no role in a geothermal system.

Such conditions occur along plate boundaries and volcanic belts, as in Iceland and the Puga valley.

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