# Chapter 28 - Multiple-Choice Questions - Page 1073: 4

The correct answer is: (a) The electron has more kinetic energy and a higher speed.

#### Work Step by Step

We can write an expression for the de Broglie wavelength of the electron: $\lambda_e = \frac{h}{m_e~v_e}$ We can write an expression for the de Broglie wavelength of the neutron: $\lambda_n = \frac{h}{m_n~v_n}$ Since they both have the same de Broglie wavelength, then: $m_e~v_e = m_n~v_n$ Since $m_e \lt m_n$, then $v_e \gt v_n$ Then, the kinetic energy of the electron must be greater than the kinetic energy of the neutron (since $K = \frac{1}{2}mv^2$) The correct answer is: (a) The electron has more kinetic energy and a higher speed.

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