Low permeability molds and low pouring temperature of the molten metal causes ......................... defect in castings.

Pressure die casting deals with casting metals of relatively ............. A ............. melting point and provides ........ B.......... production rate.

A. higher / lower,$$\,\,\,\,\,\,\,\,\,\,$$ B. higher / lower

Ceramic slurry is used in making the molds for

The voltage-arc length characteristic of a $$DC$$ arc is given by $$V=20+40L.$$ where $$L=$$ arc length in $$cm.$$ The power source characteristics can be approximated by a straight line. Open circuit is $$80V$$ and short circuit current $$1000$$Amps. The optimum arc length in $$mm$$