Which statement best describes the gas turbine's suitability as a prime mover?

• A. They require large heat exchangers for efficiency
• B. They are best used where rapid ramping and light weight are important
• C. They have highest thermal efficiency at base load
• D. They only operate at sea level

Answer: (B)

The option highlights what gas turbines excel at: quick response and high power in a compact package. A gas turbine can increase or decrease output very rapidly because fuel flow and air intake can be adjusted quickly, and the machine has relatively few moving parts compared with other prime movers. Its high power-to-weight ratio means you get a lot of generating capability from a relatively small, lightweight unit. That combination makes it ideal for applications where the plant must ramp up or down fast to follow demand or to provide peaking capacity.

In contrast, a gas turbine’s efficiency is not its strongest feature at base load, especially for simple-cycle units; they typically don’t achieve the highest thermal efficiency compared with steam plants or modern combined-cycle configurations when operated steadily. The statement about needing large heat exchangers isn’t a defining trait for gas turbines, and they don’t only operate at sea level—altitude affects performance but is not a limiting condition. So the description that best fits a gas turbine as a prime mover is its suitability for rapid ramping and light weight.