Asked by GenChem

I am wondering if my work makes sense for the following problem:

Warm objects emit electromagnetic radiation in the infra-red region. Heat lamps employ this principle to generate infra-red radiation. Water absorbs infra-red radiation with wavelengths near 2.80um. Suppose this radiation is absorbed by the water and converted to heat. A 1.00 L sample of water absorbs infra-red radiation, and its temperature increases from 20C to 30C. How many photons of this radiation are used to heat the water?

My work:
q=heat absorbed by water = mass x specific heat water x delta T
q = 1000 x 4.184 x 10
q = 41840

detalE = hc/wavelenght
wavelenght = 2.8 x 10^-6 m

deltaE = [(6.626 x 10^-34)(3.0 x 10^8)]/2.8 x 10^-6

delta E = 7.09 x 10^-20 m per photon

Proportion:
1 photon = 7.099 x 10^-20m
q = 41840
Therefore, 5.894 x 10^-16

Is this correct?
Answered by bobpursley
No. Did you read my last post?

number photons= energyneede/energyperphoton
Goodness.
Answered by GenChem
I did read your last post...you asked what q was equal to. And in this post I answered your question what q is equal to.
Answered by bobpursley
You are not with me.

Doesn't the question ask how many photons are needed?

You know the total energy needed, q.
You know the energy per photon.

number*energyperphoton=energyneeded.
Answered by uhh
5.9 x 10^23 ?
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