An immersion water heater is rated 2.0 kW. On a particular day it is switched on for 30 min.
(i) Calculate the electrical energy supplied to the water heater in joule.
(ii) Express the same energy in kilowatt-hour.
(iii) If the cost of electrical energy is ₹6.00 per kWh, determine the cost of operating the heater for that day.