# Problem: It takes 7.21 x 10 -19 J of energy to remove an electron from an iron atom. What is the maximum wavelength of light that can do this?

###### FREE Expert Solution

We are asked to calculate the maximum wavelength of light that takes  takes 7.21 x 10 -19 J of energy to remove an electron from an iron atom

Calculate the wavelength from the total energy (ΔE).

ΔE = 7.21 x 10 -19 J
h = 6.626x10-34 Js

$\overline{){\mathbf{∆}}{\mathbf{E}}{\mathbf{=}}{\mathbf{h}}{\mathbf{\nu }}}$

In the equation, the frequency of the light is used but we need wavelength. We can relate frequency and wavelength using the speed of light:

$\overline{){\mathbf{c}}{\mathbf{=}}{\mathbf{\lambda }}{\mathbf{·}}{\mathbf{\nu }}}\phantom{\rule{0ex}{0ex}}\frac{\mathbf{c}}{\mathbf{\lambda }}\mathbf{=}\frac{\overline{)\mathbf{\lambda }}\mathbf{·}\mathbf{\nu }}{\overline{)\mathbf{\lambda }}}\phantom{\rule{0ex}{0ex}}\overline{){\mathbf{\nu }}{\mathbf{=}}\frac{\mathbf{c}}{\mathbf{\lambda }}}$

c = speed of light = 3.0x108 m/s
▪
λ = wavelength, m

80% (169 ratings) ###### Problem Details

It takes 7.21 x 10 -19 J of energy to remove an electron from an iron atom. What is the maximum wavelength of light that can do this?

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Our tutors have indicated that to solve this problem you will need to apply the Photoelectric Effect concept. You can view video lessons to learn Photoelectric Effect. Or if you need more Photoelectric Effect practice, you can also practice Photoelectric Effect practice problems.

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Our data indicates that this problem or a close variation was asked in Chemistry: An Atoms First Approach - Zumdahl Atoms 1st 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl Atoms 1st 2nd Edition practice problems.