Physics Questions

The Camphor slowly dissolves in the water lowering the latter's surface tension in the immediate neighbourhood. The stronger pull exerted by the uncontaminated portion of water brings about a movement of the surface and the camphor particles are carried along with it. When after sometime the whole surface settles for the reduced tension, the movement of the camphor too short.

An electric charge always flows from a body at higher potential to a body at a lower potential irrespective of the amounts of charges contained in them. In the question , no current flows. So there is no potential difference. 

B2+ is a Paramagnetic. 

The filled orbitals are σ(1s)22, σ∗(1s)22, σ(2s)22, σ∗(2s)22. The half-filled orbitals are π(2pxx) and π(2pyy). Since it posses 2 unpaired electrons, it is Paramagnetic in nature.