What was the purpose of the invention of electricity?

Which is NOT part of an AC generator? What is difference between 500MW boiler 660MW boiler? To determine the rms value of triangular waveform? What are the physical demands of an electrician.? What is mA symbol? What are the dangers associated in vicinity of busbar? What is a pottant? How do you convert microfarad into farad? Why 380 volts line to line if connect line to neutral is 220 volts? What is the con using a 32 amp contactor instead of a 20 amp contactor? Which semiconductor have positive temperature coefficient? How do you calculate holding current of scr when latching current is given? What is Advantage of logic analyzer with built in digital pattern generator over simulator? Why would a tube light be flickering? Can factual information be presented with bias? Do ground wires have to be covered with wire insulation? What is the formula of electrode tip in electric arc furnace? Why do some appliances have step down transformers built into them? If a 0.001 and a 0.015 capacitor are placed in parallel. what would be the total capacitance of the circuit? How many amps can number eight wire carry?