# Physical Chemistry/Photoelectric Effect

#### Mwz1024

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I don't know if this is the right forum to discuss it in or not. But I have question that involves Physical Chemistry that I have no idea on how to answer.

The work function for sodium metal is 1.82 eV (electron volts). Calculate the threshold frequency and wavelenght for sodium.

Using Planck's law, dtermine the wavelength of maximum emission intensity for a blackbody with a temperature of 6000K.

I know that the first question involves the photoelectric effect.

#### cfdavid

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Mwz1024 said:
I don't know if this is the right forum to discuss it in or not. But I have question that involves Physical Chemistry that I have no idea on how to answer.

The work function for sodium metal is 1.82 eV (electron volts). Calculate the threshold frequency and wavelenght for sodium.

Using Planck's law, dtermine the wavelength of maximum emission intensity for a blackbody with a temperature of 6000K.

I know that the first question involves the photoelectric effect.

The work function is the minimum (threshold) quantity of energy needed to be absorbed by an electron in order for it to be completely ejected from it's orbit. Since E=hf ,which can then be set equal to the work function, you can divide the work function by Planck's constant to get the frequency. But first, you need to convert eV's to Joules (1eV = 1.60 x 10^-19 Joules) since J's are the units in h.

Then c=freq. x wavelength to solve for the wavelength.

Let me know if this does NOT work out.
I can't help on the second problem.

#### MoosePilot

##### Y Bombardier
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7+ Year Member
Mwz1024 said:
I don't know if this is the right forum to discuss it in or not. But I have question that involves Physical Chemistry that I have no idea on how to answer.

The work function for sodium metal is 1.82 eV (electron volts). Calculate the threshold frequency and wavelenght for sodium.

Using Planck's law, dtermine the wavelength of maximum emission intensity for a blackbody with a temperature of 6000K.

I know that the first question involves the photoelectric effect.

For the second question, I think you could probably apply the formula found on this page:

http://en.wikipedia.org/wiki/Black_body

#### Mwz1024

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15+ Year Member
Got it solved. The second question took me a while to solve. Very messy derivation.

This thread is more than 15 years old.

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