42) A thin cylindrical shell of diameter (d), length (l), and thickness (t) is subjected to an internal pressure (p). The ratio of the longitudinal strain to hoop strain is

43) Rankine's constant for a mild steel column with both ends hinged is

44) The material used in the manufacture of thermistors are

45) A metal strip is to be rolled from initial wrought thickness of 3.5 mm to a final rolled thickness of 2.5 mm in a single pass rolling mill having rolls of 250 mm diameter. The strip is 450 mm wide. The average co-efficient of friction in the roll gap is 0.

46) Find the melting efficiency for an arc welding process which has a potential of 15 volts and current rating of 250 ampares. Weld has travel speed of 6 mm/s for a cross sectional area of 18 square millimeter. Heat transfer efficiency is 0.80 and heat requir