e10 fuel contains 10% ethanol and 90% petrol. Ethanol is alcohol, this ethanol used in fuel is usually produced from agricultural waste.
It all depends on the vehicle you put the fuel in. Some vehicles need to run on higher octane fuel. Often there will be a sticker on your vehicle which will specify the minimum octane requirement for your car. You will need to put in fuel that meets this minimum octane requirement. Failure to do this can result in the engine knocking a condition where the fuel is igniting before it's meant to.
Only certain vehicles can run the e85 fuel. Check the manual for your car or contact your car dealership and ask whether your vehicle is a e85 compatible.
These numbers refer to the octane rating of the petrol. The higher the number the higher the octane rating. These numbers are what is referred to as the RON or Research Octane Number, this is a way of measuring octane level.
No, you cannot put petrol in your diesel car as it will damage it. If you have accidentally done this don't drive it but call your mechanic or roadside assistance for help.