निम्नलिखित में से कौन सा कारक प्राकृतिक चिमनी द्वारा उत्पादित ड्राफ्ट (draught) को बढ़ाता है?

In power plant engineering, the 'Plant Use Factor' is defined as the ratio of:

Which of the following is a major drawback of using a forced draught (positive pressure) system in a boiler?

What is a common serious issue caused in steam lines when a steam trap fails in a closed position?