Why do we use alternating current?

In the dark! We would just have to do with DC. As transmission losses due to inability to 'transform' DC,would be excessive it would mean that generators would have to be fairly local.

Hey! Here is the surprising answer to your question: almost ALL of the electronic devices you use everyday is powered by DC! From your wrist-watch to Ipod to laptop to TV to cellphone to you name it - it is all powered by DC.

Most electrical vehicles (trains as well as hybrid/EV cars) use DC drive-trains. Very few devices are engineered to use AC (such as poorly designed radio-alarms that tap off the frequency to keep time). As all the posters above have noted, it was problems with transmission losses due to the inability to set-up DC to a high voltage that prevented the widespread use of DC.

Today, we have several high-voltage DC links in the world, including in USA. High voltage DC transmission has a very powerful reason going for it - it isolates two different regions that might experience dynamic instability when linked with an AC link.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.