Electron/positron pairs are occasionally created out of empty space.Looking at energy-time uncertainty,how long would such particle pairs be expected to last? The mass of the electron is 9.11 * 10^-31 kg. A)3.2 * 10^-22 s B)6.4 * 10^-22 s C)1.2 * 10^-21 s D)2.5 * 10^-5 s E)5.8 * 10^-5 s

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Quizplus · Accepted Answer

The lifetime of electron/positron pairs can be estimated using the energy-time uncertainty principle, $\Delta E \Delta t \approx \hbar$, where $\Delta E$ is the energy equivalent of the mass of the electron (or positron), and $\hbar$ is the reduced Planck constant ($\approx 6.58 \times 10^{-16} \, \text{eV}\cdot\text{s}$). Given the mass of the electron is $9.11 \times 10^{-31}$ kg, its energy equivalent ($E = mc^2$) can be calculated and used to estimate the time ($\Delta t$). The correct calculation leads to a time scale on the order of $10^{-22}$ seconds, matching choice A.

Electron/positron Pairs Are Occasionally Created Out of Empty Space