A flux density of 1.2Wb/m^2 is required in the 1 mm air gap of an electromagnet having an iron path of length 1.5 m. Calculate the mmf required. Given, relative permeability of iron is 1600. Neglect leakage.

12000j is work done

im srry but ur wrong the answer is d a smooth rock, some red dirt, and an empty bird's nest.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach