1. The AWS A5.5 is a list of electrodes used to weld which type of metal?
A Copper and copper alloys.
B. Carbon steels.
C. Low alloy steels.
D. Gray and ductile iron.
E. Corrosion-resistant steels.

An inventor claims to have developed a reversed heat engine (ie. a heat pump) which is able to deliver 10 kj heat into the room at 20°c from outside ambient temperature of -10°c by consuming only 2 kj electricity in winter. this claim is a)-impossible b)-possible only if the heat pump is ideal c)-practically possible d)-unable to be assessed as it depends on the working fluid used in the heat pump.