ANS:A - evaporative capacity

The amount of water evaporated in kilograms per kilogram of fuel burnt in a boiler is called the evaporative capacity of a boiler. Evaporative capacity refers to the boiler's ability to convert water into steam per unit of fuel burnt. It is a measure of the boiler's effectiveness in producing steam from the heat generated by burning fuel. Higher evaporative capacity indicates that the boiler can generate more steam per unit of fuel, which is desirable for achieving higher productivity and efficiency in various industrial processes. Evaporative capacity is an important parameter for assessing the performance of a boiler and is often used in boiler specifications and performance evaluations. It is influenced by factors such as the design, size, and operating conditions of the boiler, as well as the type and quality of the fuel being burnt. Other terms such as evaporation efficiency, thermal efficiency, and steam load also relate to the performance and operation of boilers, but evaporative capacity specifically refers to the rate of water evaporation per unit of fuel burnt.