4. 10 marks An electrical contact material is produced by infiltrating copper into a porous tungsten carbide (WC) compact. The density of the final composite is 12.3g/cm3. Assuming that all of the pores are filled with copper, calculate: (a) The volume fraction of copper in the composite? (b) The volume fraction of pores in the WC compact prior to the infiltration? (c) The original density of the WC compact before infiltration