why do some microwave ovens rotate the food container? suppose the metal walls form a rectangular cavity of dimensions 37 cm * 37 cm * 20 cm. when 2.45-ghz microwaves are continuously introduced into this cavity, reflection of incident waves from the walls sets up standing waves with nodes at the walls. along the 37-cm dimension of the oven, how many nodes exist (excluding the nodes at the wall) and what is the distance between adjacent nodes? (no heating occurs at these nodes, so rotating the food container gives more even heating of the food.)