Define energy conversion efficiency .Also state the first law of thermodynamics and mention its significance through fuel input as in petrol. An IC engine has an input of 500 KWh. Energy equivalent to 350 KWh is utilized for running a motor. What is the energy conversion efficiency?

Energy conversion efficiency is a measure of how effectively a system converts input energy into useful output energy. It is defined as the ratio of useful output energy to the input energy, expressed as a percentage. In other words, it quantifies the fraction of input energy that is converted into the desired form of output energy, while the rest is lost as waste heat or other forms of energy.

The first law of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed in an isolated system; it can only change forms. This fundamental principle asserts that the total energy of a closed system remains constant over time, with energy transformations occurring between different forms such as mechanical, thermal, chemical, and electrical energy.

In the context of fuel input, such as petrol used in an internal combustion (IC) engine, the first law of thermodynamics highlights the conservation of energy principle. When petrol is burned in an IC engine, the chemical energy stored in the fuel is converted into heat energy through combustion. This heat energy is then partially converted into mechanical energy to drive the piston and ultimately produce useful work, such as moving a vehicle or generating electricity. However, not all of the energy released during combustion is converted into mechanical work; some is lost as waste heat through exhaust gases, cooling systems, and friction within the engine.

Now, let's calculate the energy conversion efficiency using the provided values:

Input energy (fuel input) = 500 kWh
Output energy (useful energy for running the motor) = 350 kWh

Energy conversion efficiency = (Output energy / Input energy) × 100%
= (350 kWh / 500 kWh) × 100%
= 0.7 × 100%
= 70%

Therefore, the energy conversion efficiency of the system is 70%. This means that 70% of the input energy from the petrol is effectively utilized to run the motor, while the remaining 30% is lost as waste heat and other forms of energy during the energy conversion process.