Which of the following statements regarding the periodic table of elements is true?

If jill was traveling at 300 miles in 4 hours due south what was his velocity in miles per minute a) 75 miles per hour due south b) .02 miles per second due south c) .5 miles per second due south d) 1 mile per hour due south

Positrons are spontaneously emitted from the nuclei of

The discovery of the electron as a subatomic particle was a result of