An electron is allowed to move freely in a closed cubic box of length of side 10cm. The uncertainity in its velocity will be:
a. 3.35 x 10⁻³ m/sec
b. 5.8 x 10⁻⁴ m/sec
c. 4 x 10⁻⁵ m/sec
d. 4 x 10⁻⁶ m/sec