JEE Advanced levelNumerical answerDifficulty 3 of 3as150
An electron is confined within Δx=0.20nm. Take the minimum momentum uncertainty Δp=h/(4πΔx) and estimate the least kinetic energy as (Δp)2/2me. Give the answer in eV to two decimals. Use h=6.626×10−34Js, me=9.1×10−31kg, 1eV=1.6×10−19J.
Numerical answer type, answer in eV, tolerance 0.01.
Answer: 0.239 eV
Δp=2.636×10−25kgms−1. Then K=(Δp)2/2me=3.819×10−20J=0.239eV.