Given : The mass of electron is 9.11 10-31 kg, Planck constant is 6.626 10-34 J s, the uncertainty involved in the measurement of velocity within a distance of 0.1 A is
- 5.79 105 m s-1
- 5.79 106 m s-1
- 5.79 107 m s-1
- 5.79 108 m s-1
Answer
(2) 5.79 106 m s-1
Solution
By Heisenberg's uncertainty principle:
x m v = h4
⇒ v = h4 m x
Here x = 0.1 A = 1 10-11 m
⇒ v = 6.626 10-344 3.14 9.11 10-31 1 10-11
= 6.626 10-341.144 10-40
= 5.79 106 m s-1
Answer: (2)