A. determine the sign of the charge on each rod.
b. compute the ratio of the linear charge densities on the two rods, .

Answer.

The electric field due to a negative charge points radially in from all directions (because a positive test charge placed near it would feel a force pointing toward it). Generally, electric field lines always point from positive charges and toward negative charges.

Your question I s incomplete, please endeavor you update your question with the necessary parameters.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%