The atomic number gives you the number of protons element x has. Since the mass of protons and neutrons are almost similar(around 1 amu), the mass number can be thought of as the sum of protons and neutrons. so if element x whose atomic number is 40 has a mass number of 82, then we know that 42 of those must be neutrons.
Answer:
to check for errors.
Explanation:
since some of the components of the scale are metallic, they are prone to rusting which would cause error in reading of the scale so there is organized checking if the scale to correct that.
hope it helps .
I think it may be c, 1.7 v. I work with electricity a lot.