Why does a white unprinted paper not get heated in microwave while potato does?

A white unprinted paper does not contain water molecules, while potatoes do. Microwaves work by heating water molecules through a process called dielectric heating. When microwaves interact with water molecules, the molecules vibrate and generate heat. This is why foods that contain a lot of water, like potatoes, heat up quickly in a microwave, while dry foods like white unprinted paper do not.

In addition, the color of a material can also affect how it heats in a microwave. Darker materials tend to absorb more microwaves than lighter materials, which is why a black piece of paper would heat up more quickly than a white piece of paper.

To summarize, the combination of the lack of water molecules and the light color of white unprinted paper makes it resistant to heating in a microwave.