Uncertainity principle Definition and 52 Threads

In application of uncertainity principle i read,if we suppose electron in a sphere of radius r then we assume unertainity of position as delta 'r',instead of taking diameter as uncertainity.Though it will not effect the calculations at all,but conceptually and physically what could be the reason...

in my problem i am told that the x-component of the velocity of a 2x10^-4 kg mass is measured to an accuracy of +_ 10^-6 m/s. i need to find the limit of the accuracy with which the particle can be located along the x-axis. the uncertainity principle delta(x) * delta(Px)>= h/4pi i have...