Answer:The correct answer is option C.
Explanation:
Wavelength is defined as distance tween two troughs or crests.
Frequency is defined number of cycles of the wave occurring in one second.
Radioactive waves are the electromagnetic waves with longer wavelength and shorter frequency.
[tex]Frequency=\frac{c}{Wavelength}[/tex]
c = speed of the light.
[tex]Frequency\propto \frac{1}{Wavelength}[/tex]
So from the given waves , the wave with longest wavelength and shortest frequency will be radioactive wave. And that wave is Wave 3 of option C.
Hence ,option C is correct answer.
