A given mass of a gas occupies 900 ml in dry state at stp. The same mass when collected over water at 15 ℃ and 750 mm pressure occupies 1 l volume. Find the aqueous tension at 15 ℃.

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.