Answer:
L₀ = 15.12 fermi
Explanation:
From Einstein's special theory of relativity's consequence of length contraction, we know that:
L₀ = L √(1 - v²/c²)
where,
L₀ = Length of the object (electron) measured by observer at rest = ?
L = Length of the object (electron) measured by observer in relative motion
L = 10 fermi
v = relative speed = 0.75 c
c = speed of light
Therefore,
10 fermi = L₀√(1 - 0.75²c²/c²)
10 fermi = L₀√(1 - 0.5625)
10 fermi = L₀√0.4375
10 fermi/0.66 = L₀
L₀ = 15.12 fermi
