Question

wavelength (meters) which electromagnetic wave has the shortest wavelength? which electromagnetic wave would have a wavelength approximately the size of the tip of a pencil? which electromagnetic wave has the longest wavelength?

Explanation:

Step1: Compare wavelengths

From the given values: Radio ($10^{3}$), Microwave ($10^{2}$), Infrared ($10^{-5}$), Visible ($0.5\times10^{-6}$), Ultraviolet ($10^{-8}$), X - ray ($10^{-10}$), Gamma Ray ($10^{-12}$). The smallest value is $10^{-12}$ (Gamma Ray).

Step2: Estimate pencil - tip size

A pencil - tip is about $10^{-5}$ meters. Looking at the wavelengths, Infrared has a wavelength of $10^{-5}$ meters.

Step3: Compare wavelengths for longest

The largest value among the given wavelengths is $10^{3}$ (Radio).

Answer:

Gamma Ray; Infrared; Radio