Answer
$3.00\times10^{-10}eV/c^2$.
Work Step by Step
Use equation 28–2 to calculate the uncertainty in the energy of the muon.
$$\Delta E \geq \frac{\hbar}{\Delta t}$$
From that, find the uncertainty in its mass.
$$\Delta E = (\Delta m)c^2$$
$$\Delta m \geq \frac{\hbar}{c^2\Delta t}$$
$$=\frac{(1.055\times10^{-34}J\cdot s)(eV/1.60\times10^{-19}J)}{c^2(2.30\times10^{-6}s)}$$
$$=3.00\times10^{-10}eV/c^2$$
