(a) State Faraday's law of electromagnetic induction.（2 Marks）

　　（b） Vehicles such as buses may be powered by electric motors. The motors on these buses use batteries which need to be charged often. This is normally done by connecting to a fixed electrical supply whilst the bus is parked.

　　The photograph shows a bus on a road in South Korea. This road enables the batteries to chargewhilst the bus is in motion.

　　Under the road there are electric cables,connected to a 440V 60 Hz supply. These generate magnetic fields. There is a coil inside the charging device which is located below the floor of the bus. This enables the batteries on the bus to charge

　　*i）Explain how this system works.（3 Marks）

　　ii）It is not necessary for the cable to be installed under the entire length of the road. Thebatteries used to nower these buses can be much smaller than those used in other electric busesExplain why the cables do not need to be installed under the entire length of the road and whythe batteries can be smaler.（3 Marks）