A brass billet is to be excluded from its initial diameter of $$100mm$$ to a final diameter of $$50mm$$. The working temperature is $${700^ \circ }C$$ and the extrusion constant is $$250$$ $$MPa.$$ The force required for extrusion is

In Oxyacetylene gas welding, temperature at the inner cone of the flame is around

Match the following

The arc - voltage characteristics of a $$DC$$ power source has a linear power source characteristic of $$V=20+40L,$$ where $$V$$ is the arc voltage in volts and $$L$$ is the arc length in $$cm.$$ The static volt-ampere characteristic of the power source is approximated by a straight line with open circuit voltage $$=80V$$ and short circuit current is $$600Amps,$$ determine the optimum arc length for maximum power