Around casting is 0.1 m in diameter and 0.56 m in length. another casting of the same metal is rectangular in cross section, with a width-to-thickness ratio of 2, and has the same length and cross-sectional area as the round casting. both pieces are cast under the same conditions. what is the difference in the solidification times of the two castings?

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.