(a) (i) Due to change in length and area of cross-section of a conductor, resistance of conductor changes while resistivity does not change. Why? (ii) Conductors of electric toasters and electric iron are made of an alloy rather than a pure metal. Why? (iii) Define the S.I. unit of electric current. 5 OR (b) (i) How many bulbs of resistance 8 2 each should be connected in parallel combination to draw a current of 2 A from a battery of 4 V? Q 5 (ii) Name the device used for measuring electric current. How is it connected in a circuit ? (iii) State Joule's law of heating. (