Photovoltaic cells convert solar energy into electricity. Calculate the waveleng

Question

Photovoltaic cells convert solar energy into electricity. Calculate the wavelength of light (in nm) required for tantalum (phi = 6.81 times 10^-8 J) to emit an electron. Then determine whether or not tantalum could be used to generate electricity from the sun? Assume that most of the electromagnetic energy from the sun is in the visible region near 500 nm. Yes. the threshold wavelength is larger than the wavelength of the sun so electricity is generated. No, the threshold wavelength is larger than the wavelength of the sun 90 electricity will not be generated.

Explanation / Answer

The minimum energy of photon needed must be equal to work function of titanium sothat the electron can just be ejectred.

So, Energy of photon = 6.81 * 10-19 J

But, E = h c / Wave length

6.81 * 10-19 = 6.626 * 10-34 * 3 * 108 / Wave length

Therefore, wave length = 2.92 * 10-7 m = 292 * 10-9 m = 292 nm

This is not in the visible region but it is in Ultra violet region.

No, the therhold energy is larger than the wavelength of sun, electricity will not be generated.

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