A particle is confined within a spherical radius of one femtometer(10^-15 m)? Its momentum can be expected to be about- 1. 20 keV/c 2. 200 keV/c 3. 200 MeV/c 4. 2 GeV/c How should I go about using HUP on a problem like this one? I tried substituting x=10^-15 meters in px=h/4 pi but the answer is wrong. Apparently because the problem is about volume.