School bells are made of metals because metals are
- A.Malleable
- B.Sonorous
- C.Ductile
- D.Lustrous
Correct answer
Explanation
The correct answer is B, Sonorous. Metals produce a ringing sound when struck, a property called sonority, which is why bells are made of metal.
Sonorous means 'producing a deep, ringing sound'. When a metal object is hit, its tightly packed atoms vibrate together and the vibrations last for some time, giving a clear, loud ring. This is why school bells, temple bells, gongs and many musical instruments such as cymbals are made of metals or alloys, for example bell metal, an alloy of copper and tin. Most non-metals, such as wood or sulphur, give only a dull thud when struck. Sonority is one of the physical properties listed for metals in school science, along with malleability, ductility, lustre and conductivity.
A is wrong: malleability is the property of being beaten into thin sheets.
C is wrong: ductility is the property of being drawn into wires.
D is wrong: lustre is the shine of a metal surface, not its sound.
Exam tip: sonorous = rings when struck (bells); malleable = sheets; ductile = wires; lustrous = shiny.
Practice Questions
View allConsider the following animals :
1. Hedgehog
2. Marmot
3. Pangolin
To reduce the chance of being captured by predators, which of the above organisms rolls up/roll up and protects/protect its/their vulnerable parts?
- A.1 and 2
- B.2 only
- C.3 only
- D.1 and 3
Show answer
Hedgehogs and pangolins curl into a tight ball when threatened, covering the soft belly and face with spines or scales; marmots do not.
Read the full explanation →Which one of the following is used in preparing a natural mosquito repellent?
- A.Congress grass
- B.Elephant grass
- C.Lemongrass
- D.Nut grass
Show answer
Lemongrass and its close relative citronella grass yield aromatic oils that keep mosquitoes away, so they are the base of many natural repellents.
Read the full explanation →Which one of the following devices is non-ohmic ?
- A.Conducting copper coil
- B.Electric heating coil
- C.Semi conductor diode
- D.Rheostat
Show answer
A diode does not obey Ohm's law: the current through it is not proportional to the voltage across it. An ohmic conductor gives a straight-line graph of current against voltage, so its resistance stays constant at a fixed temperature.
Read the full explanation →What is the formula mass of anhydrous sodium carbonate? (Given that the atomic masses of sodium, carbon and oxygen are 23 u, 12 u and 16 u respectively)
- A.286 u
- B.106 u
- C.83 u
- D.53 u
Show answer
Anhydrous sodium carbonate is Na₂CO₃, and 2 × 23 + 12 + 3 × 16 = 106 u. Formula mass is the sum of the atomic masses of all the atoms in one formula unit of an ionic compound.
Read the full explanation →Which one of the following minerals is used as a fuel in nuclear power stations ?
- A.Bauxite
- B.Quartz
- C.Feldspar
- D.Pitchblende
Show answer
Pitchblende, or uraninite, is the chief ore of uranium, the fuel used in most nuclear power stations. Pitchblende is a heavy, black mineral made mostly of uranium oxide.
Read the full explanation →