Energy, Water & Material Resources — Chapter quiz · Physics & Environmental Science, Grade 12

Evaluate resources through conservation, replenishment, life-cycle boundaries, and equal service.

Problem 1

Which of these is a fossil fuel?
  1. Wind
  2. Uranium
  3. Sunlight
  4. Coal
Answer and explanation

Coal

Coal, oil, and natural gas are the three fossil fuels. Uranium is a nuclear fuel, and sunlight and wind are renewable.

Problem 2

Nuclear power plants generate electricity by...
  1. splitting heavy uranium nuclei in a process called fission
  2. fusing hydrogen nuclei together
  3. capturing heat from magma at the surface
  4. burning uranium in air the way coal is burned
Answer and explanation

splitting heavy uranium nuclei in a process called fission

Nuclear plants use fission — splitting uranium-235 nuclei — to release heat that boils water and spins a turbine.

Problem 3

Which of the following is a renewable energy source?
  1. Natural gas
  2. Solar power
  3. Coal
  4. Oil
Answer and explanation

Solar power

Solar power is renewable because the Sun keeps shining; coal, oil, and natural gas are all nonrenewable fossil fuels.

Problem 4

A wind turbine rated at 4 MW produces an average of 1.4 MW of power over a full year. What is its capacity factor, as a percent?
Answer and explanation

35 %

Capacity factor = average output / maximum output = 1.4 / 4 = 0.35 = 35%.

Problem 5

A watershed is best described as...
  1. a plant that removes salt from seawater
  2. a saltwater sea
  3. the area of land that drains to a common body of water
  4. an underground cavern of water
Answer and explanation

the area of land that drains to a common body of water

A watershed is all the land from which water drains into one shared river, lake, or bay.

Problem 6

Which activity is the LARGEST single use of freshwater worldwide?
  1. Filling swimming pools
  2. Drinking water in homes
  3. Cooling in factories
  4. Irrigating crops in agriculture
Answer and explanation

Irrigating crops in agriculture

Agriculture, mostly through irrigation, uses roughly 70% of all freshwater — far more than homes or industry.

Problem 7

Of all freshwater used worldwide, agriculture takes about 70% and industry about 20%. What percent is left for homes and cities?
Answer and explanation

10 %

The uses total 100%: 100 - 70 - 20 = 10% for domestic use in homes and cities.

Problem 8

The fertile top layer of soil that most crops grow in is called the...
  1. A horizon (topsoil)
  2. bedrock
  3. C horizon (parent rock)
  4. deepest layer of the profile
Answer and explanation

A horizon (topsoil)

The A horizon is the dark, fertile topsoil, rich in humus, where most plant roots grow.

Problem 9

Which practice best conserves soil?
  1. Removing all hedgerows and windbreaks
  2. Planting cover crops and using no-till farming
  3. Plowing straight up and down steep hills
  4. Leaving fields bare and exposed after harvest
Answer and explanation

Planting cover crops and using no-till farming

Cover crops and no-till farming keep roots in the ground and the surface covered, holding soil in place against erosion.

Problem 10

Which statement about Earth's soil and mineral resources is TRUE?
  1. Metal ores are renewable resources
  2. Soil always erodes more slowly than it forms
  3. Fertile topsoil can be lost far faster than nature rebuilds it
  4. Topsoil forms within just a few weeks
Answer and explanation

Fertile topsoil can be lost far faster than nature rebuilds it

Topsoil forms over centuries but can erode in decades, so it can be lost far faster than it forms — which is why it must be conserved. Ores are nonrenewable.

Problem 11

Explain the following claim and supply a valid example or counterexample: Low direct operational CO₂ does not mean zero life-cycle impacts.
Answer and explanation

Both commonly make heat to drive a turbine; fossil fuels oxidize carbon compounds, while nuclear fission changes nuclei. Low direct operational CO₂ does not mean zero life-cycle impacts.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 12

Independent chapter check: Plant A delivers40 MJ electricity from100 MJ fuel; B delivers50 MJ from100 MJ. Direct fuel factors are80 and70 g CO₂/MJ input. Compare direct emissions per delivered MJ, then name an omitted term.
Answer and explanation

A:8000/40=200 g/MJ delivered. B:7000/50=140 g/MJ. Upstream leakage, transport or construction is omitted; this direct comparison is not a complete life-cycle ranking.

A:8000/40=200 g/MJ delivered.

B:7000/50=140 g/MJ.

Upstream leakage, transport or construction is omitted; this direct comparison is not a complete life-cycle ranking.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical or environmental mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 13

Explain the following claim and supply a valid example or counterexample: Renewable describes replenishment, not zero impact or unlimited site availability.
Answer and explanation

12/(2×24)=.25=25%; it is not conversion efficiency. Renewable describes replenishment, not zero impact or unlimited site availability.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 14

Independent chapter check: A5 kW system has30% capacity factor for2000 h. Find generated energy. If storage returns80% of an allocated500 kWh, how much useful stored energy returns?
Answer and explanation

Generation=5×0.30×2000=3000 kWh. The allocated storage input returns400 kWh and loses/transfers100 kWh under the stated boundary; do not apply the storage loss to energy that bypasses it.

Generation=5×0.30×2000=3000 kWh.

The allocated storage input returns400 kWh and loses/transfers100 kWh under the stated boundary; do not apply the storage loss to energy that bypasses it.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical or environmental mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 15

Explain the following claim and supply a valid example or counterexample: Water withdrawn can partly return; consumption is the portion not promptly returned to the same system.
Answer and explanation

10% for the remaining category in that stated model. Do not treat these shares as universal current observations. Water withdrawn can partly return; consumption is the portion not promptly returned to the same system.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 16

Independent chapter check: An aquifer receives8 million m³/year recharge, loses2 million to streams and is pumped at9 million. Find annual storage change and a limitation of predicting well depth from it.
Answer and explanation

Δstorage=8−2−9=−3 million m³/year. Exact water-level change also needs aquifer geometry, storage properties and spatial pumping/flow patterns.

Δstorage=8−2−9=−3 million m³/year.

Exact water-level change also needs aquifer geometry, storage properties and spatial pumping/flow patterns.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical or environmental mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 17

Explain the following claim and supply a valid example or counterexample: A mineral reserve is an economically recoverable subset of resources under specified conditions.
Answer and explanation

It may form much more slowly than it erodes; erosion can remove essential productive layers within the planning period. A mineral reserve is an economically recoverable subset of resources under specified conditions.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 18

Independent chapter check: A2000 kg ore batch has3% target metal and75% recovery. Find contained, recovered and unrecovered target metal, then name a separate soil-quality measure.
Answer and explanation

Contained=60 kg; recovered=45 kg; unrecovered target=15 kg. Infiltration, organic matter, pore structure or measured erosion can characterize soil quality separately from mineral yield.

Contained=60 kg; recovered=45 kg; unrecovered target=15 kg.

Infiltration, organic matter, pore structure or measured erosion can characterize soil quality separately from mineral yield.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical or environmental mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 19

Can recycling have nonzero impacts?
Answer and explanation

Yes; transport, processing energy, losses, and disposal of residuals matter.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 20

Why test sensitivity to lifespan?
Answer and explanation

Different use counts can reverse the ranking when production and operating impacts trade off.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 21

Independent chapter check: Reusable production energy is180 units with3 units/use; disposable energy is9 units/use. Find break-even and energy difference after50 uses.
Answer and explanation

180+3n=9n gives n=30 uses. At50, reusable=330 and disposable=450, a120-unit advantage in this hypothetical energy category; other impacts need separate accounts.

180+3n=9n gives n=30 uses.

At50, reusable=330 and disposable=450, a120-unit advantage in this hypothetical energy category; other impacts need separate accounts.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the physical or environmental mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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