(a) Compare constant current method and constant voltage method of charging batteries. (6)

(b) The filament of a 230V lamp takes a current of 0.261A when working at its normal temperature 2000°C. The temperature coefficient of the tungsten filament material can be taken as 0.005°C⁻¹ at 0°C. Find the appropriate current which flows at the instant of switching on the supply to the cold lamp, which can be considered to be at a room temperature of 20°C. (10)