What are the answers to questions 14-18 regarding roofing materials, pH, and water pressure?

Here are the answers to the questions:

14. The following are properties for the felt underlay when used on roof surfaces EXCEPT

    • D. Accelerates the conductivity of roofing sheets to timber Felt underlay typically acts as an insulator, reducing heat transfer, not accelerating it. It also provides moisture protection and sound deadening.

15. The green coating which is formed on copper roofing materials is an indication of

    • A. The formation of a protective coating The green coating on copper, known as patina, is a result of oxidation and forms a stable, protective layer that prevents further corrosion of the copper.

16. The PH value of water means,........................

    • C. The degree of acidity and alkalinity in water pH is a scale used to specify the acidity or basicity (alkalinity) of an aqueous solution.

17. Water head is a simple explanation of........................

    • D. The vertical distance from water level to draw off Water head refers to the vertical height of a column of water, which determines the pressure it exerts at a certain point.

18. When calculating the TOTAL PRESSURE in liquids, two quantities are mu .These are,........................

    • A. Intensity of pressure and area acted upon Total pressure (force) exerted by a liquid is calculated by multiplying the intensity of the pressure by the area over which it acts ($F = P \times A$).