Engineering MCQs

The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K₀ + at. where, K is the thermal conductivity and T is the temperature (in °K). The units of ‘a’ in SI system will be

by
W/m.k
W/m
W/m.k²
None, A is just a number
✅ The correct answer is option C.

In a heat exchanger with steam outside the tubes, a liquid gets heated to 45°C, when its flow velocity in the tubes is 2 m/s. If the flow velocity is reduced to 1 m/s, other things remaining the same, the temperature of the exit liquid will be

by
Less than 45°C
More than 45°C
Equal to 45°C
Initially decreases and remains constant thereafter
✅ The correct answer is option B.