5. Explain the following: a) Ductile b) sonorous
Answers
- Ductility is a measure of a material's ability to undergo significant plastic deformation before rupture or breaking, which may be expressed as percent elongation or percent area reduction from a tensile test. According to Shigley's Mechanical Engineering Design significant denotes about 5.0 percent elongation.
- having a pleasant, deep and full sound
Explanation:
(i) Malleable: This means that metals can be beaten into thin sheets with a hammer. The property which allows the metals to be hammered into thin sheets is called malleability.
Aluminium metal can be hammered to form alumimium foils.
(ii) Ductile: This means that metals can be drawn (or stretched) into thin wires. The property which allows the metals to be drawn into thin wires is called ductility.
Copper metal can be drawn into thin copper wires (used as electric wires).
(iii) Lustrous: This means that metals have a shiny appearance. The shiny appearance of the metals is called metallic lustre.
Gold metal is used for making jewellery because of its shiny lustre.
(iv) Conductors: This means that metals allow heat and electricity to pass through them easily.
Copper metal is used in making cooking utensils because of its high heat conductivity.
(v) Sonorous: This means that metals make a ringing sound when we strike them. The property by virtue of which metals make a ringing sound is called sonority.
Metal sheets are used for making bicycle bells and temple bells.