Solving Photon Energy with Equations: Am I Right?

[kuruman]

I can't read that. There are too many erasures. Can you type it up, please?

 

[meher4real]

I can't read that. There are too many erasures. Can you type it up, please?

- N(inter)=5.6x10^18 x 180 x (1-e^(-0.32x0.1x10^-3)) = 1.03x10^13 photons
- E(abs) = N(inter)xE(photon)
= 2.50 x 10^-6 J
- Energy required to heat the paper :
Q=m x Cp x T = 80x10^-3kg x 1.34 J/kg x 233° = 24.97 J
- Number of photons required :
24.97/2.42x10^-19 J = 1.032x10^20 photons

 

[kuruman]

- N(inter)=5.6x10^18 x 180 x (1-e^(-0.32x0.1x10^-3)) = 1.03x10^13 photons

This number is too low by several orders of magnitude. The left-hand side is OK, the right-hand side is not. You must have made a mistake somewhere.

 

[meher4real]

This number is too low by several orders of magnitude. The left-hand side is OK, the right-hand side is not. You must have made a mistake somewhere.

i used the thickness of the paper which is 0.1 mm ?! you said that is 1 mm can you explain why ?

 

[kuruman]

You used the correct thickness of the paper 0.1 mm as given by the problem. What I am saying is that 5.6x10^18 x 180 x (1-e^(-0.32x0.1x10^-3)) is NOT 1.03x10^13. You need to redo this calculation correctly.

 

[meher4real]

You used the correct thickness of the paper 0.1 mm as given by the problem. What I am saying is that 5.6x10^18 x 180 x (1-e^(-0.32x0.1x10^-3)) is NOT 1.03x10^13. You need to redo this calculation correctly.

The rest is ok ?

 

[kuruman]

The rest is ok ?

No, the rest is not Ok. Cut a piece of paper into a square of side 1 cm. Do you really believe it weighs 80 grams or 80x10^-3kg?

 

[meher4real]

No, the rest is not Ok. Cut a piece of paper into a square of side 1 cm. Do you really believe it weighs 80 grams or 80x10^-3kg?

g to kg isn't 10^-3 ?

You used the correct thickness of the paper 0.1 mm as given by the problem. What I am saying is that 5.6x10^18 x 180 x (1-e^(-0.32x0.1x10^-3)) is NOT 1.03x10^13. You need to redo this calculation correctly.

- N(inter)=5.6x10^18 x 180 x (1-e^(-(0.32x0.1x10^-3)) = 3.23x10^16 photons
- E(abs) = N(inter)xE(photon)
= 7.8 x 10^-3 J

 

[kuruman]

g to kg isn't 10^-3 ?

- N(inter)=5.6x10^18 x 180 x (1-e^(-(0.32x0.1x10^-3)) = 3.23x10^16 photons
- E(abs) = N(inter)xE(photon)
= 7.8 x 10^-3 J

I agree with those numbers. Now what?

 

[meher4real]

I agree with those numbers. Now what?

What's wrong with weight 80x10^-3kg ?

 

[kuruman]

A standard, letter-sized 8.5"×11", sheet of paper weighs 4 to 5 grams. Do you really believe that if you cut a square piece 1 cm on the side out of that sheet, it will weigh 80 grams?

 

[meher4real]

A standard, letter-sized 8.5"×11", sheet of paper weighs 4 to 5 grams. Do you really believe that if you cut a square piece 1 cm on the side out of that sheet, it will weigh 80 grams?

weight x 1 cm^2 ?

 

[kuruman]

weight x 1 cm^2 ?

The whole sheet of paper is 4 grams. If you cut a piece of that paper any size, any shape, can it weigh 20 times as much as the entire sheet? Think!

 

[meher4real]

The whole sheet of paper is 4 grams. If you cut a piece of that paper any size, any shape, can it weigh 20 times as much as the entire sheet? Think!

huh you're right, weight/1cm^2

 

[kuruman]

So what is the mass of 1 cm² of paper? Read carefully and understand what you are given.

 

[meher4real]

So what is the mass of 1 cm² of paper? Read carefully and understand what you are given.

I found Energy required to heat paper = 0.40 J
number of photons required = 1.612x10^18 photons

 

[kuruman]

I found Energy required to heat paper = 0.40 J
number of photons required = 1.612x10^18 photons

I didn't ask you what energy is required to heat the paper and I didn't ask you for the number of photons required. I asked you to find the correct mass of the paper that is heated up. You have repeatedly avoided answering my questions which I am only asking to guide your thinking. Your refusal to answer them indicates to me that you reject my help. If that's the case, I will stop helping you.

 

[meher4real]

I didn't ask you what energy is required to heat the paper and I didn't ask you for the number of photons required. I asked you to find the correct mass of the paper that is heated up. You have repeatedly avoided answering my questions which I am only asking to guide your thinking. Your refusal to answer them indicates to me that you reject my help. If that's the case, I will stop helping you.

Not at all !
I really appreciate your time and efforts to help me out with the problem, can't thank you enough, i was literally lost but It's a matter of time for me because your process takes too long to find the solution.
As i said before I'm on rush and I'm working on the last problem rn.

 

[kuruman]

OK, then you set the pace but we cannot move forward unless you answer my questions. This process is not mine. It is how we proceed in this forum. If you focus on just getting the answer without paying attention to the process that leads you to it, it is unlikely that you will understand what you're doing and why. I can end this 49 posting thread by giving you the complete solution, but I will not do it for two reasons: (a) it is against forum rules and (b) I don't believe it will benefit you if I do.