The atomic number for fluorine is 9, so the nucleus of the atom has: a) 4 protons and 5 neutrons b) 9 protons and no neutrons c) 9 electrons and 9 protons d) 9 protons and no electrons

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.