The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275 kJ/mol What wavelength in m of light has sufficient energy to dislodge an electron from the surface of sodium?

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The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275 kJ/mol What wavelength in m of light has sufficient energy to dislodge an electron from the surface of sodium?

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Answer 1 · 2016-11-02T00:40:50

I got $430 n m$ $430nm$

Explanation:

You need $275 k J$ $275kJ$ to dislodge one mol of electrons so we need:

$\frac{275 \times 10^{3}}{6 \times 10^{23}} = 4.6 \times 10^{- 19} J$ $(275xx10^3)/(6xx10^23)=4.6xx10^-19J$ for one electron only.

We can use Einstein`s relationship between energy $E$ $E$ and frequency $f$ $f$ and between frequency and wavelength $λ$ $lambda$ :

$E = h f = h \frac{c}{λ}$ $E=hf=hc/lambda$

to find the wavelength ( $h$ $h$ is Plank`s Constant and $c$ $c$ the speed of light).
We get:
$λ = h \frac{c}{E} = (6.6 \times 10^{- 34}) \cdot \frac{3 \times 10^{8}}{4.6 \times 10^{- 19}} = 4.3 \times 10^{- 7} m = 430 n m$ $lambda=hc/E=(6.6xx10^-34)*(3xx10^8)/(4.6xx10^-19)=4.3xx10^-7m=430nm$

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The energy required to dislodge electrons from sodium metal via the photoelectric effect is 275 kJ/mol What wavelength in m of light has sufficient energy to dislodge an electron from the surface of sodium?

1 Answer

Explanation:

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