Problem 1.3 6th ed.

[Jerome Mercado 2J]

Which of the following happens when the frequency
of electromagnetic radiation decreases? Explain your reasoning.
(a) The speed of the radiation decreases.
(b) The wavelength of the radiation decreases.
(c) The extent of the change in the electrical field at a given point decreases.
(d) The energy of the radiation increases.

I chose answer C since the others do not display the correct relationships with frequency. That is the only reasoning I had. I was wondering what is the reasoning solely answer C without looking at the other answers.

[marisaimbroane1J]

Answer C has to do with the amplitude of the wave. When the extent of change (the slope of the wave--think derivative) decreases, that means the amplitude is decreasing and the wave is being broadened. If you decrease the frequency, the waves become more spread out and therefore the slope of the wave will decrease.

[Bruce Chen 2H]

I believe the answer is C as the frequency decreases, so does the slope of the wave.

[Henry Krasner 1C]

C is the answer,
As frequency increases, wavelength will decrease as they are inversely related and energy will increase as they are positively correlated. Also speed is a constant. So C is the only viable answer. In addition, the increased wavelength size, the less variability you will get over time, which would be less true at a higher frequency.