How many moles are there in 50.5 atoms ba

Define dew point. i am writing this part to be able to ask the question

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

When a device is used in a circuit in which the voltage is 81 v the current flowing through the device is 3 a what is the resistance of the device