Using a cathode ray tube , what did Thomson confirm

Avehicle has an oil leak that is causing the entire oil pan to be wet, but inspection reveals no exact source after cleaning off the oil residue. technician a says to install a fluorescent dye in the crankcase and operate the engine, then re-inspect for leaks with a special light (black light). technician b says the oil leak may be coming from a source at the top of the engine, such as a valve cover gasket. who is correct?

What will a positive and a negative charge do if they are separated from each other?

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply