Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for_________________?

Related Mcqs:

Fouling factor for a heat exchanger is given by (where, U1 = heat transfer co-efficient of dirty surface U2 = heat transfer co-efficient of clean surface) ?

A. U1 – U2 B. 1/U1 – 1/U2 C. 1/U2 – 1/U1 D. U2 – U1...

The ratio of total radiating power to the absorptivity of the body depends upon the _____________ as per Kirchoff‟s law?

A. Wavelength of radiation B. Nature of the body C. Temperature of the body D. None of these...

The unit of heat transfer co-efficient in SI unit is____________________?

A. J/M2°K B. W/m2°K C. W/m°K D. J/m°K...

A hot liquid is kept in a big room. The logarithm of the numerical value of the temperature difference between the liquid and the room is plotted against time. The plot will be very nearly a/an___________________?

A. Ellipse B. Straight line C. Parabola D. Circular arc...

For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area___________________?

A. Increases B. Decreases C. Remain constant D. Passes through a maxima...