Suntan Sally put on her bathing suit and relaxed in a room that was pitch black. At the same time Tanline Timmy put on his bathing suit and relaxed in a room filled with bright light. A couple hours later Suntan Sally had a bad sunburn while Tanline Timmy wasn't? How is this possible?

Answer 1

the infrared portion of the solar spectrum is responsible for sunburn

infrared is not part of the spectrum visible to humans

the pitch black room must have had infrared radiation sources

Timmy's bright lights emitted very little infrared