A50-ml beaker only has a scale that measures 10, 20, 30, and 40 ml. what is the uncertainty associated with the 50 ml beaker.

Usually the uncertainty of a graduated cylinder is given however if it is not, then it is simply assumed to be equal to half of the least interval of that instrument. In this case, the least interval is 10 ml, so half of this is 5 ml. Hence, the graduated cylinder has an uncertainty of +/- 5 ml

lithosphere and asthenosphere

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.