Final answer:
Students investigate the heating efficiency of microwaves and the role of a microwave oven's metal grid in preventing microwaves from escaping. They calculate the efficiency from the temperature rise of water and examine destructive interference by changing the water's position inside the oven.
Step-by-step explanation:
To analyze the efficiency of heating in a microwave oven, students are tasked with conducting several experiments and recording their observations. The structure of the microwave oven door, featuring a metal grid, prevents microwaves from escaping due to the holes in the grid being smaller than the microwave's wavelength. Students then heat water to measure temperature gain (the ΔT) and calculate heating efficiency based on a 1000 W power output. Additionally, by removing the rotating turntable and placing a cup of water in various positions, students observe the effects of destructive interference on the heating process.