The cost of energy to operate an industrial refrigerator that consumes 5 kW power working 10 hours per day for 30 days will be (Given that the charge k.W.h of energy = Rs. 4)

To calculate the cost of energy for the industrial refrigerator, we first determine the total energy consumption in kilowatt-hours (kWh). Energy (E) is the product of power (P) and time (t). The refrigerator has a power rating of 5 kW and operates for 10 hours per day, resulting in a daily consumption of 50 kWh (5 kW × 10 h). Over a period of 30 days, the total energy consumed is 1,500 kWh (50 kWh/day × 30 days). The cost of electricity is then calculated by multiplying the total energy consumption by the unit rate. Given the charge is Rs. 4 per kWh, the total cost is 1,500 kWh × Rs. 4/kWh = Rs. 6,000. This follows the standard formula where Cost = Power × Time × Rate.