Electroplating prevents 
(a) corrosion
(b) passing of current
(c) dissociation
(d) shining   ​

The frequency of direct current (d.c.) is :

A 5^(@)C rise in the temperature is observed in a conductor by passing some current. When the current is doubled, then rise in temperature will be equal to

(a) Define corrosion, what is the nature given to corrosion of iron ? (b) Name the colour of coating formed on silver and copper when exposed to air. (c ) List two damages caused by corrosion and suggest, how these can be prevented.

A 2^(@)C rise in temperature is observed in a conductor passing a current. When the current is tripled. The rise in temperature will be

(a) Explain the term "corrosion" with an example. Wriite a chemical equation to show the peocess of correcsion of iron. (b) What special name is given to the corrosion of iron ? (c ) What type of chemical reaction is involved in the corrosion of iron ? (d) Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.

A rise of temperature of 4^(@)C is observed in a conductor by passing a current. If the current is tripled, the rise of temperature will be