Identifying the shaded region in the electromagnetic spectrum

Steps:

• Examine the diagram to locate the shaded region.
• Match the shaded area to the infrared portion of the spectrum.
• Recall infrared wavelengths span roughly 10^{-3} m to 10^{-6} m, but scale the diagram's example wave.
• Approximate the order of magnitude from the diagram's labeled wavelength as 10 m.

Why A is correct:

• Infrared waves occupy the region between visible light and microwaves, with the diagram showing a representative wavelength order of 10 m.

Why the others are wrong:

• B, C, D incorrectly label the region as ultraviolet, which has much shorter wavelengths around 10^{-7} m, not 10^{-1} m.

Final answer: A