BEST IELTS Academic Reading Test 436

BEST IELTS Academic Reading Test 436

IELTS Academic Reading Test
IELTS academic reading practice test

Coronal Mass Ejections

Quebec, 13th March 1989: At 2.45 a.m. the province’s entire power grid crashed. The blackout affected six million people in north-eastern Canada for up to nine hours, shutting schools and businesses, and closing down the Montreal Metro and Dorval Airport. Meanwhile, a red glow appeared in the night sky over most of the world, and as far south as Texas and Cuba people were able to see multi-coloured shifting lights in the sky.

At the same time, in space, some satellites spun out of control for several hours. The blackout in Quebec was caused when the safety systems in the electricity network sensed a power surge caused by electric energy flowing through the ground. In fact, most of North America was experiencing increased electrical activity and around 200 power grid problems were reported within minutes of each other.

IELTS Academic Reading Test

All the events had one source: days earlier a massive wave of energy had erupted from the sun and crashed into earth’s magnetic field. These events are called coronal mass ejections (CMEs). CMEs are similar to solar flares in so far as they both produce highenergy particles that are dangerous to living organisms.

They are both explosions on the surface of the sun that continue for minutes and even hours, and they can release enough energy to power the USA for a million years. They happen when areas of intense solar activity called sunspots appear and magnetic fields associated with sunspots connect, sending huge amounts of energy away from the sun. The most dangerous emissions from these ejections are protons (subatomic particles with a positive electrical charge) and X-rays.

IELTS Academic Reading Test

The sun has an eleven-year cycle of activity in which the intensity of activity on its surface changes, the most intense period (called a solar maximum) being characterised by the appearance of sun spots and solar flares. Like solar flares, CMEs are more likely to be produced during the period of maximum solar activity. However, unlike solar flares, which produce high-energy particles near the surface of the sun, CMEs carry a large volume of material much further into interplanetary space.

Fortunately, the iron core spinning at the centre of the Earth generates a magnetic force field around the planet called the magnetosphere. This magnetic field reaches out thousands of miles into space and protects us from all but the most violent CMEs. When the solar material collides with the earth’s magnetosphere, it triggers geomagnetic storms of the kind that affected Quebec so dramatically.

IELTS Academic Reading Test

CMEs and flares are classified as B, C, Mor X according to how strong they are. Each letter of the scale is ten times more powerful than the previous one; so an X flare is ten times more powerful than an M and a hundred times more powerful than a C flare. Within each letter scale there is a finer gradation from 1 to 9.

In reality, C class flares are too weak to affect the Earth; M class flares can cause radio blackouts in areas near the poles and cause weak radiation storms that can be dangerous for astronauts. However, the X class flares can cause considerable damage at ground level. Although the flare that affected Quebec was strong,; the most powerful flare ever recorded was in 2003 – a flare so powerful that it overloaded satellite sensors.

IELTS Academic Reading Test

It will typically take a CME three to five days to affect the Earth after leaving the sun. Observing the ejection of CMEs from the sun provides early warning of geomagnetic storms. The Solar and Heliospheric Observatory, a European-built spacecraft that orbits the Earth, continuously observes the CMEs to determine if they are travelling in the direction of the Earth as damage to satellites and communications can be very serious.

Communications satellites are generally the most exposed to damage from CMEs – these satellites are often in high orbits. When the solar material hits a satellite, it becomes charged with electricity and a component can become damaged by the current or by highenergy particles penetrating the satellite. As we have become more and more dependent upon high technology and other systems that can be affected by electrical currents and energy particles, the danger from flares and CMEs has intensified. But could a solar flare or CME be large enough to cause a global disaster? It is impossible to give an answer.

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IELTS Academic Reading Test

Choose the correct letter, A, B or C.

27. What did the CME of 13th March 1989 NOT do?

A. disrupt daily life for some Canadians

B. cause an unusual phenomenon in Texas

C. stop all flights across Canada

D. increase ground electricity in North America

28. What produces the magnetosphere?

A. high-energy particles

B. geomagnetic storms

C. metal at the centre of the Earth

D. sunspots

IELTS Academic Reading Test

29. What does the Solar and Heliospheric Observatory do?

A. It tells scientists when a CME is approaching the Earth.

B. It communicates with other satellites orbiting the Earth.

C. It tells scientists if a CME will cause a global disaster.

D. It circles the sun in a high orbit.

30. How can CMEs damage satellites?

A. by sending them out of high orbit

B. by bombarding them with high-energy particles

C. by stopping communication between them and the sun

D. by melting components inside them

IELTS Academic Reading Test

Which characterises the following?

A. solar flare


C. both

Write the correct letter, A, B or C, next to Questions 31-35.

31. It is produced during the solar maximum.

32. It carries material far into interplanetary space.

33. It produces high-energy particles.

34. It may affect the Earth.

35. It happens near the sun’s surface.

IELTS Academic Reading Test

Which flares are mentioned in the text as having the effects below?

A. C flares

B. M flares

C. X flares

Write the correct letter, A, B, or C, next to Questions 36-40.

36. There would be damage to electrical equipment on the Earth’s surface.

37. You couldn’t listen to the radio in certain places.

38. You wouldn’t notice the effect.

39. You would be harmed if you were working in space.

40. It would seriously damage satellite equipment.

IELTS Academic Reading Test


BEST IELTS Academic Reading Test 436

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IELTS Academic Reading Test

27. C

28. C

29. A

30. B

31. C

32. B

33. C

34. C

35. A

36. C

37. B

38. A

39. B

40. C

IELTS Academic Reading Test

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