(7.21) Calculate the heat flow (per square meter) across a 50 mm thick ceramic tile with an outer surface temperature of 700 C and an inner surface temperature of 30 C, given a thermal conductivity of 0.0837 J/s. m.K.

Julia would be observing a. static electricity was caused by her sweater rubbing against her shirt and transferring electrons. she didn't touch anything metal, so that would cancel out b.she most likely didn't rub her sweater against her hair either, so that cancels out c.she also didn't scoot across the carpet while trying to take her sweater off, that cancels out d.so that leaves a.a. is correct.