Buckminster fullerene, which looks like a football, is an allotropic form of
- A.Phosphorus
- B.Sulfur
- C.Carbon
- D.Tin
Correct answer
Explanation
The correct answer is C, Carbon. Buckminsterfullerene is C60, a cage-shaped molecule of sixty carbon atoms.
The sixty atoms are arranged in 12 pentagons and 20 hexagons, the same pattern as the panels of a football, which is why the molecule is also called a buckyball. It is named after the American architect Buckminster Fuller, whose geodesic domes have a similar shape. It was discovered in 1985 by Harold Kroto, Robert Curl and Richard Smalley, who received the 1996 Nobel Prize in Chemistry. Diamond, graphite and graphene are the other well-known allotropes of carbon.
A is wrong: phosphorus has allotropes such as white, red and black phosphorus, but no fullerene.
B is wrong: sulphur's allotropes are rhombic and monoclinic sulphur.
D is wrong: tin exists as grey tin and white tin, not as a football-shaped cage.
Exam tip: allotropes of carbon are diamond, graphite, graphene and fullerene (C60); fullerene was discovered in 1985 and won the 1996 Nobel.
Practice Questions
View allThe speed of the wind is measured by
- A.wind vane
- B.wind rose
- C.barometer
- D.anemometer
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An anemometer measures how fast the wind is blowing; its name comes from the Greek word anemos, meaning wind.
Read the full explanation →Brilliance of diamond is due to
- A.interference of light
- B.diffraction of light
- C.polarization of light
- D.total internal reflection of light
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Light that enters a cut diamond is reflected again and again inside it before it escapes, which makes the stone sparkle.
Read the full explanation →Which one of the following is NOT an electromagnetic wave ?
- A.Light wave
- B.Radio wave
- C.Sound wave
- D.Micro wave
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Sound is a mechanical wave that needs a medium to travel, while the other three are electromagnetic waves. Sound travels as a longitudinal wave of compressions and rarefactions in air, water or solids, which is why it cannot pass through a vacuum.
Read the full explanation →Which one of the following is NOT true for an electromagnetic wave ?
- A.Electromagnetic wave transports energy and momentum
- B.Electromagnetic wave can be polarized and reflected
- C.Electromagnetic wave is longitudinal
- D.Electromagnetic wave propagation is described by the varying electric and magnetic fields
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Electromagnetic waves are transverse, not longitudinal, so this statement is false. In an electromagnetic wave the electric field and the magnetic field oscillate at right angles to each other and both at right angles to the direction in which the wave travels.
Read the full explanation →Which one of the following frequency ranges is sensitive to human ears ?
- A.0-200 Hz
- B.20-20,000 Hz
- C.200-20,000 Hz only
- D.2,000-20,000 Hz only
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The normal human ear hears sound from about 20 hertz to 20,000 hertz, the audible range. Frequency, measured in hertz, is the number of vibrations per second, and it decides the pitch of a sound: the higher the frequency, the shriller the note.
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