the mass number of fluorine (F) is 19
C. 19
They all are correct , so with that being said anyone of them can be right
Answer:
Most common insulation materials work by slowing conductive heat flow and--to a lesser extent--convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space.
Explanation:
To be effective, the reflective surface must face an air space.
