How much heat is absorbed by a 74g iron skillet when its temperature rises from 7oc to 28oc?

Awoman stands a distance d from a loud motor that emits sound uniformly in all directions. the sound intensity at her position is an uncomfortable 2.0×10-3 w/m2. at a distance 2.6 times as far from the motor, what are (a) the sound intensity and (b) the sound intensity level relative to the threshold of hearing?

Which is not true about oxygen-17 and oxygen-18?

Which type of energy is transferred by convection currents?