Sapling Homework week 2 problem 5

[Lucy Weaver 1K]

HI! I'm having a lot of trouble solving the 5th problem on sapling.

I muplipled planks constant by the speed of light, got 1.98644582 × 10-25 m3 kg / s2, then divided that by 9.33 * 10^-4 to get E. I found that E= 2.13 *10^-22.Then I divided that by 100 to turn it from centimeters to meters. I got 2.13*10^-24. Then I divided 51.5/2.13*10^-24 and it is giving me an incorrect.

I am not sure what I'm doing wrong, so if someone is able to help me understand that would be great!

[Lucy Wang 2J]

Hey! I think you are doing it correct but you just need to convert from cm to m before you find Energy (J).

[HannahRobinson3L]

Hi! I think you have to convert the wavelengths from cm to meters before you calculate the energy, or else you end up with a different answer. If you convert the wavelength first, you should get an energy of 2.13*10-20. Hope this helps.

[Margia Adriano 2A]

Hi! I think you should try (Planck's constant)(speed of light)/(9.33*10^-6) instead of (Planck's constant)(speed of light)/(9.33*10^-4). When you divide the latter by 100 instead of doing it like the former equation, I believe you get different answers. Hope this helps! If I'm wrong, please correct me!

[Emma Strassner 1J]

Hi! I think you have to convert the wavelengths from cm to meters before you calculate the energy, or else you end up with a different answer. If you convert the wavelength first, you should get an energy of 2.13*10-20. Hope this helps.

Hi, I agree with this. Converting from cm to meters first is necessary to get the right answer for E. If you wait until after you won't be converting the right units, which is why you would get the wrong answer.

[idella 1D]

Where do you get the 9.33x10^-6 from?

[Melanie Lin 3E]

Where do you get the 9.33x10^-6 from?

Hi Idella! The problem said that the wavelength was 9.33x10^-4 cm so you have to convert it to meters before plugging it into the E=hc/wavelength. In meters, the wavelength would be 9.33x10^-6.

[idella 1D]

Where do you get the 9.33x10^-6 from?

Hi Idella! The problem said that the wavelength was 9.33x10^-4 cm so you have to convert it to meters before plugging it into the E=hc/wavelength. In meters, the wavelength would be 9.33x10^-6.

thank you! i really appreciate it :')

[AlyssaMaynard1C]

Hi! I think you should try (Planck's constant)(speed of light)/(9.33*10^-6) instead of (Planck's constant)(speed of light)/(9.33*10^-4). When you divide the latter by 100 instead of doing it like the former equation, I believe you get different answers. Hope this helps! If I'm wrong, please correct me!

Where is the 9.33*10^6 coming from?

[AlyssaMaynard1C]

Where do you get the 9.33x10^-6 from?

Hi Idella! The problem said that the wavelength was 9.33x10^-4 cm so you have to convert it to meters before plugging it into the E=hc/wavelength. In meters, the wavelength would be 9.33x10^-6.

I'm seeing the wavelength as 851nm on the question

[Juliana Rosales 1H]

I had trouble with this one too! Lol

[Juliana Rosales 1H]

I had trouble with this one too! Lol