Practice Problem  [ENDORSED]

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Fiona Grant 1I
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Joined: Fri Apr 06, 2018 11:03 am

Practice Problem

Postby Fiona Grant 1I » Sun Apr 15, 2018 3:51 pm

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 10^5 m/s. The work function for sodium is 150.6 kJ/mol.

A. What is the kinetic energy of the ejected electron?

For this problem, I want to use the equation E(k)=(1/2)(m(e-))(v(e-)^2) to find kinetic energy. The velocity, but not the mass, of the electron is given. How should I go about solving this?

Natalie Noble 1G
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Joined: Thu Feb 01, 2018 3:02 am
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Re: Practice Problem  [ENDORSED]

Postby Natalie Noble 1G » Sun Apr 15, 2018 3:52 pm

You are correct to use the formula


The problem gives you the velocity of the electron and you don’t need the work function they give you for this problem.

The mass of an electron is a constant and it is:

9.10938 x 10^-31 kg

Now you have all the parts for the formula and all you need to do is plug them in.

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