Collapsible tubes for tooth paste are produced by ________ extrusion?

In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes________?

The temperature at which plastic layer formation takes place during carbonisation of coal varies from ________ °C?

Co-efficient of performance of a Carnot cycle refrigerator operating between – 23°C and + 27°C is ________?

Fuel gases containing hydrocarbons (e.g. coke oven gas) are not preheated before burning, mainly because ________?

Hydraulic radius is the ratio of ________?