## 1B. 25 7th Edition

$\lambda=\frac{h}{p}$

Mark 1D
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

### 1B. 25 7th Edition

Howdy ya'll. 1B.25 states "What is the minimum uncertainty in the speed of an electron confined within a lead atom of diameter 350 pm? Can somebody explain how to obtain the solution please. Thanks

Edward Xie 2E
Posts: 63
Joined: Fri Sep 28, 2018 12:23 am

### Re: 1B. 25 7th Edition

You use Heisenberg's Indeterminacy Equation:

$\Delta p \Delta x\geq \frac{h}{4\pi}$

The question gives the uncertainty in position (delta x) by stating the diameter of the lead atom, 350 pm. To keep it in SI units, it becomes 3.50 x 10^-10 m.

To find the only unknown, delta p (uncertainty in momentum), we plug all known values into the equation and solve:

Delta p = 6.63x10^-34/ (4pi x 3.50x10^-10m)

Once delta p is obtained, plug that value into the equation $\Delta p = m * \Delta v$ to get your answer.

Ronald Thompson 1F
Posts: 59
Joined: Fri Sep 28, 2018 12:25 am

### Re: 1B. 25 7th Edition

Great explanation