241.

Energy in the form of heat is wasted when a machine is operated. This heat is generated due to ___________.

• burning

• friction

• combustion

• lubrication

Acetic Acid is another name for which of the following?

• Vinegar

• Baking Soda

• Copper Sulphate

• Magnesium Oxide

A ......... thread is actually stronger than a steel wire.

• wool

• cotton

• jute

• nylon

The process of depositing a layer of any desired metal on another metal by means of electricity is called ...........

• Electroplating

• Galvanisation

• Rusting

• Crystallisation

The salt concentration (measured as salinity in parts per thousand), is..........% in sea.

• 10-20

• 30-35

• 40-50

• 60-70

A change in which one or more new substances are formed is called .................

• Physical Change

• Chemical Change

• Rusting

• Galvanisation

The property of metals by which they can be beaten into thin sheets is called ................

• ductility

• malleability

• viscosity

• tensile strength

The salt concentration (measured as salinity in parts per thousand), is greater than .............% in hypersaline lagoons.

• 50

• 100

• 150

• 200

The temperature at which a solid melts to become a liquid at atmospheric pressure is called..........

• crystallisation

• melting point

• evaporation

• galvanisation

The melting point of ice is ............K.

• 253.16

• 263.16

• 273.16

• 283.16