7. The ratio of the energy required to produce the artificial draught (expressed in metres head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
Correct Answer: The steam pressure in the cylinder is not allowed to fall below the atmospheric pressure.
9. A condenser maintains a low pressure (below atmospheric) so as to obtain the maximum possible energy from steam and thus to secure a high efficiency.