## Question 1A.3 c

$c=\lambda v$

Gabriella Bates 2L
Posts: 94
Joined: Thu Jul 11, 2019 12:15 am

### Question 1A.3 c

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

I’m confused on this question, and the detailed answer didn’t make sense to me. Can someone please explain? Thank you

Justin Seok 2A
Posts: 88
Joined: Sat Aug 24, 2019 12:15 am

### Re: Question 1A.3 c

I also wasn't 100% clear on this question, but I kinda took it to mean that since there aren't as many oscillations, the electrical field wouldn't change as quickly since it takes a longer time for each wave to oscillate. Not the most technical explanation but hopefully it kinda helps clear things up.

Maya Pakulski 1D
Posts: 88
Joined: Thu Jul 11, 2019 12:17 am

### Re: Question 1A.3 c

Can somebody explain to me why it isn't B?

britthanul234
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

### Re: Question 1A.3 c

This has to do with the frequency, which you can assume is an oscillation or wave. There are not as much oscillations, so the electrical field will not change as quickly. That is why the answer is what it is.

alicechien_4F
Posts: 94
Joined: Sat Jul 20, 2019 12:15 am

### Re: Question 1A.3 c

Maya Pakulski 3D wrote:Can somebody explain to me why it isn't B?

The answer (b) states that the wavelength of the radiation decreases. This not correct because with the equation C = λv, wavelength (λ) and frequency (v) are inversely proportional. If you decrease the frequency, the λ must increase to compensate since C (speed of light) remains constant. Hope this helped!

Ashley Nguyen 2L
Posts: 86
Joined: Sat Aug 17, 2019 12:18 am

### Re: Question 1A.3 c

According to the equation c = λv, where c is a constant representing the speed of light in a vacuum, λ (wavelength) and v (frequency) are indirectly proportional. If frequency were to increase, wavelength must decrease. In this question, the frequency decreases, so wavelength must therefore increase. By this logic, we can eliminate B as a potential answer choice. The speed of the radiation would not change because c, the speed of light, is a constant, so A is also incorrect. As the frequency of electromagnetic radiation decreases, it would actually decrease in energy because a particle would would complete less cycles per second, so D is also incorrect. Through the process of elimination C would be the right answer. You know this is true because the energy of electromagnetic radiation directly affects the oscillations of affected charged particles, so by decreasing the energy of said radiation, the effect of the electrical field on charged particle would also decrease.