Determine the percent error if the density of mercury is 13.534g/ml and you measured the density to be 13.000g/ml

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions

Acm ruler with main graduations from 1 to 10 from left to right there are 10 secondary graduations between each of the main graduations there is a line that begins. at the left end of the ruler 10 secondary graduations to the left of the “1 main graduation the right end of the line ends on the eighth secondary graduation to the right of 3 how long is the line

Is this correct if not can u correct me