Q. The measurement of the electron position is associated with an uncertainty in momentum, which is equal to 1 × 10⁻¹⁸ g cm s⁻¹. The uncertainty in electron velocity is, (mass of an electron is 9 × 10⁻²⁸ g)
A) 1 × 10¹¹ cm s⁻¹
B) 1 × 10⁹ cm s⁻¹
C) 1 × 10⁶ cm s⁻¹
D) 1 × 10⁵ cm s⁻¹
Explanation
[Solution from source] Δv = Δp/m = (1 × 10⁻¹⁸ g cm s⁻¹)/(9 × 10⁻²⁸ g) ≈ 1.1 × 10⁹ cm s⁻¹. Both quantities are already in CGS units, so no conversion is needed, and converting only one of them gives the wrong power of ten. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.