Calculate the magnitude of the electric field at the center of a square with sides 24.1 cm long if the corners, taken in rotation, have charges of
1.16c,
2.32î¼c,
3.48î¼c
4.64î¼c
(all positive).

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.