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Q.25

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Found in: Page 1114

### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

# \| An electron with 2.00 mathrm{eV of kinetic energy collides with the atom shown in FIGURE EX38.24.a. Is the electron able to excite the atom? Why or why not?b. If your answer to part a was yes, what is the electron's kinetic energy after the collision?

a. The electron is able to excite the atom.

b. The kinetic energy of the electron after the collision is 0.5 eV

See the step by step solution

## part (a) step 1 : given information

a. We have a quantized system with three discrete energy levels 0, 1.5 and 4 eV . An electron with kinetic energy equals to 2 eV collides with that system. We want to know if that energy, for the electron, is sufficient to excite that system. This excitation can occurs under the following condition:

Energy of the electron

where is the energy difference between and j energy levels in that system. Since we have three states, therefore all energy differences we have are

(doesn't satisfy the excitation condition )

As a result of the above analysis, the electron can excite the system from the first to the second energy level because it has a kinetic energy larger than the difference in energies between level 1 and 2 .

## part (b) step 1 : given information

Our system we have which is the atom in our case absorbs an energy equals to and the electron's kinetic energy after collision becomes as follows