Read the following passage.
A. The northern lights, or aurora borealis, are displays of coloured light in the night sky of the northern hemisphere. In the southern hemisphere the same thing is called the southern lights, or aurora australis. Both happen near Earth's magnetic poles, and this is why northern Canada is one of the best places to see them. In the Canadian North, auroras can be seen almost every night from August to May, and they are most common around the spring and fall equinoxes. Astronauts on the International Space Station, which orbits at about the same height as the lights, see them at eye level.
B. The lights begin at the Sun, which blasts electrons and protons into space in a stream called the solar wind. Earth's magnetic field acts as an invisible shield that steers this wind around the planet, but its field lines are dragged and stretched until they snap back like an elastic band. This throws charged particles down toward Earth, where they collide with gases in the upper atmosphere. Each collision makes a tiny flash, and billions of flashes in a row make the aurora seem to dance. When the Sun is very active, the lights reach farther south: on the night of May 10 to 11, 2024, they were filmed in Boucherville, near Montreal.
C. An aurora's colour depends on which gas is hit and at what height. Most northern lights shine 100 to 300 kilometres above the ground, though some reach 600 kilometres. Green, the colour seen most often, comes from oxygen at 100 to 300 kilometres, while oxygen higher up, at 300 to 400 kilometres, glows red. A pink or dark red fringe sometimes appears along the lower edge, produced by nitrogen at around 100 kilometres. Hydrogen and helium can give blue and purple light, but these colours are hard for human eyes to see against the night sky.
D. Watching the lights needs no special equipment. They usually appear a few hours after sunset and grow stronger around midnight. Anyone watching should go far from city lights and check the aurora forecast and the local weather, since clouds, snow or rain and a full Moon all make the lights hard to see. Summer trips to the far north seldom work, because the sky there does not get dark in summer. Those who cannot travel can watch AuroraMAX, a camera in Yellowknife, Northwest Territories, that turns on each evening at sunset during the aurora season.
E. Not given in any of the above paragraphs.
Decide which paragraph, A to D, has the information given in each statement below. Select E if the information is not given in any of the paragraphs.
AI explanationShows the answer. Tap to open.
Correct Answer: B
Why this is correct: Look at Paragraph B. The Sun blasts particles into space as the solar wind. Earth's magnetic field is an invisible shield that steers this wind around the planet. Unseen means invisible, and a shield is a barrier.
Passage Reference: Earth's magnetic field acts as an invisible shield that steers this wind around the planet, but its field lines are dragged and stretched until they snap back like an elastic band.
Tips: This is about how our planet is protected from material sent out by the Sun. Check what the barrier does with that material.
Why the other options are wrong:
- A: In Paragraph A, the lights happen near Earth's magnetic poles. It does not describe a shield that turns the Sun's particles away.
- C: Paragraph C explains which gases give which colours. It does not say what protects the planet.
- D: Paragraph D gives advice on when and where to watch. Nothing there blocks material from the Sun.
- E: The invisible shield is described in Paragraph B. It steers the solar wind around Earth.
Correct Answer: C
Passage Reference: Green, the colour seen most often, comes from oxygen at 100 to 300 kilometres, while oxygen higher up, at 300 to 400 kilometres, glows red.
Why this is correct: The clue is in Paragraph C. Green is the colour seen most often. It comes from oxygen at 100 to 300 kilometres. So the most frequent shade is made by oxygen.
Tips: This is about the shade people notice most frequently. Check which gas makes it.
Why the other options are wrong:
- A: Paragraph A calls the lights coloured, but it names no colour and no gas.
- B: Paragraph B explains that particles hit gases in the upper atmosphere. Which gas makes the most common colour is not stated.
- D: Paragraph D is about how to watch the lights. It does not discuss colours.
- E: Paragraph C gives this. Green is seen most often, and it comes from oxygen.
Correct Answer: A
Passage Reference: In the Canadian North, auroras can be seen almost every night from August to May, and they are most common around the spring and fall equinoxes.
Why this is correct: Look at Paragraph A. In the Canadian North, auroras can be seen almost every night from August to May. That is about ten months, which is most of the year.
Tips: Think about how often the display appears in the far north. Check whether the time span given covers most of the year.
Why the other options are wrong:
- B: Paragraph B talks about one night in May 2024 near Montreal. How many nights the lights appear in the North is not part of it.
- C: Paragraph C gives heights and colours. It does not say on how many nights the lights can be seen.
- D: Paragraph D mentions the aurora season but does not say the lights appear almost every night in it.
- E: Paragraph A has this. In the Canadian North, auroras show up almost every night from August to May.
Correct Answer: E
Passage Reference: The northern lights, or aurora borealis, are displays of coloured light in the night sky of the northern hemisphere.
Why this is correct: Paragraph A gives the names aurora borealis and aurora australis. It does not say who first used these names. No paragraph mentions a scientist in Canada naming the lights.
Tips: A name can appear without its author. Look for the person who chose it.
Why the other options are wrong:
- A: Paragraph A lists the names of the lights. It says nothing about who chose them.
- B: Paragraph B explains how the lights form. It does not mention any names or the people behind them.
- C: Paragraph C matches gases with colours. It does not tell you where the name came from.
- D: Paragraph D gives viewing advice and a camera in Yellowknife. It does not say who named the lights.
Correct Answer: D
Passage Reference: Anyone watching should go far from city lights and check the aurora forecast and the local weather, since clouds, snow or rain and a full Moon all make the lights hard to see.
Why this is correct: Paragraph D gives advice to viewers. They should go far from city lights and check the aurora forecast. A dark place is one far from city lights, and a forecast is a prediction.
Tips: Look for the word 'should'. That is where the advice is.
Why the other options are wrong:
- A: Paragraph A names good places to see the lights, but it gives viewers no steps to follow.
- B: Paragraph B mentions a night when the lights were filmed near Montreal. It does not tell viewers what to do.
- C: Paragraph C notes that some colours are hard for our eyes to see. It gives no advice about dark places or forecasts.
- E: The advice is in Paragraph D. It tells viewers to go far from city lights and check the forecast.
Correct Answer: C
Passage Reference: A pink or dark red fringe sometimes appears along the lower edge, produced by nitrogen at around 100 kilometres.
Why this is correct: Look at Paragraph C. A pink or dark red fringe sometimes appears along the lower edge. It is produced by nitrogen, not oxygen. So a different gas makes the pink edge.
Tips: Look at the pinkish edge on some displays. Check which gas makes it, and whether it is oxygen.
Why the other options are wrong:
- A: Paragraph A calls the lights coloured, but it does not describe any edge or say which gas makes it.
- B: Particles colliding with gases are part of Paragraph B. Nitrogen and a pink edge are not.
- D: Clouds and a full Moon come up in Paragraph D as things that hide the lights. Colours are not discussed there.
- E: Paragraph C describes the pink fringe along the lower edge and says nitrogen causes it.
Correct Answer: B
Passage Reference: Each collision makes a tiny flash, and billions of flashes in a row make the aurora seem to dance.
Why this is correct: The answer is in Paragraph B. Each collision makes a tiny flash. Billions of flashes in a row make the aurora seem to dance. Small bursts of light are these flashes.
Tips: This is about what looks like movement in the sky. Check how small the bursts are and how quickly they come.
Why the other options are wrong:
- A: Astronauts seeing the lights at eye level is the point in Paragraph A. Why the lights seem to move is not explained.
- C: Paragraph C gives the height of each colour. It does not explain any movement.
- D: In Paragraph D, the lights grow stronger around midnight. Getting brighter is different from seeming to dance.
- E: Paragraph B explains the dancing look. It comes from billions of tiny flashes in a row.
Correct Answer: D
Passage Reference: Summer trips to the far north seldom work, because the sky there does not get dark in summer.
Why this is correct: Look at Paragraph D. Summer trips to the far north seldom work. The reason is that the sky there does not get dark in summer. A sky that is not dark is too bright to see the lights.
Tips: Think about a trip north in the warm season. Check why such a trip usually does not go well.
Why the other options are wrong:
- A: Paragraph A gives the months from August to May. It does not explain that summer skies stay too light.
- B: Paragraph B describes a night in May when the lights were seen far south. It says nothing about summer trips.
- C: Some colours are hard to see against the night sky, as Paragraph C notes. That is about colour, not about summer light.
- E: The reason summer trips seldom work, a sky that does not get dark, is given in Paragraph D.
Correct Answer: E
Passage Reference: Those who cannot travel can watch AuroraMAX, a camera in Yellowknife, Northwest Territories, that turns on each evening at sunset during the aurora season.
Why this is correct: Paragraph D describes AuroraMAX, a camera in Yellowknife. It says people who cannot travel can watch it. Nothing in the text links the camera to airlines or flight plans.
Tips: Ask why the camera exists. Check whether the text gives any reason at all.
Why the other options are wrong:
- A: Paragraph A mentions astronauts on the space station, not airlines or any camera.
- B: Paragraph B mentions filming near Montreal. Yellowknife and airlines are not part of it.
- C: Paragraph C gives heights in kilometres. It does not say why a camera was set up.
- D: Paragraph D tells you who can use the camera. It does not give airlines as the reason it was built.
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