## HW 1.5 [ENDORSED]

Celeste Martinez 1K
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### HW 1.5

The homework problem asks us to "arrange the following types of photons of electromagnetic radiation in order of increasing energy: y-rays, visible light, ultraviolet radiation, microwaves, x-rays"
Are we suppose to look at an image/chart in order to figure this out or are we suppose to calculate the energy on our own?

nelquosey
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Joined: Fri Apr 06, 2018 11:02 am

### Re: HW 1.5  [ENDORSED]

To calculate anything about frequency or energy you would need to be given wavelength. This question is testing general knowledge of electromagnetic radiation. The question assumes that you know the order.

EllenRenskoff-1C
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### Re: HW 1.5

The answer key says that gamma rays have the highest energy, though in table 1.1 on pg. 4 it did not seem like there was enough information to distinguish whether x-rays or gamma rays have higher energy. How would we figure out which one has the higher amount of energy in a problem that's more general like this one?

Caitlyn Ponce 1L
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### Re: HW 1.5

I also had the same question. X-rays and gamma rays have identical information in the previously mentioned table and I'm not sure how to differentiate the two.

AnthonyDis1A
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### Re: HW 1.5

The textbook table is technically correct since the energy potential of both waves have a lot of overlap. However, one can differentiate the two conceptually: gamma rays are nuclear in origin, whereas X-rays have an electronic source. I guess the solution ranked gamma radiation as higher in energy than X-rays because most gamma radiation examples (i.e. nucleus decay) are harnessed more frequently, man-made or not, and inflict actual/potential destruction (i.e. bombs or spontaneous solar eruptions). (?)

Jacy Black 1C
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Joined: Fri Apr 06, 2018 11:01 am

### Re: HW 1.5

I had the same question for 1.5. I think the key is the combination of two things: the table on pg. 4 as someone else noted above, and the table on pg.6 showing the electromagnetic spectrum and the range of wavelengths. While table 1.1 on page 4 differentiates different energy levels for most of the different waves of light, it doesn't differentiate between the energy levels for X-rays and "v"-rays. Figure 1.9 on page 6 shows the wavelengths of the different light waves. If you remember,

-Energy=(wavelength)*(frequency)
-energy is proportional to the frequency, and therefore energy has an inverse relationship to the wavelength.

Figure 1.9 shows the wavelengths, differentiating between the X-rays and the "v"-rays. With the knowledge that the higher energy light wave is the one with the shortest wavelength, it is clear that the v-rays have the highest energy.

I hope this helps!

Joanna Pham - 2D
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Joined: Fri Apr 06, 2018 11:04 am

### Re: HW 1.5

If we were given a question like this on a test, will we be expected to remember where each category falls on the electromagnetic spectrum?

Also, why is it that Energy = (wavelength)*(frequency)? This appears to follow the equation given in the book, c=(wavelength)*(frequency), but why isn’t c being used here? We are given the value of c, but I don’t see why you could change it to calculate the energy of something such as the UV rays..

Chem_Mod
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### Re: HW 1.5

You should familiarize with the relative order of the different types of electromagnetic waves.

With regards to confusion of x-rays and gamma-rays, gamma-rays have the higher frequency and the higher energy of the two.

Energy of a photon = h*frequency

c = wavelength*frequency.