Which of the following is a reason for reheating steam in a turbine?

Reheating steam in a turbine is primarily done to prevent excess condensation in the low-pressure stages of the turbine. When steam expands through the turbine, its pressure and temperature drop significantly, particularly in the lower pressure sections. If the steam cools too much, it can begin to condense into water. This condensation can lead to several problems, including a loss in turbine efficiency and potential mechanical damage due to water droplets impacting the turbine blades.

Reheating the steam after it has passed through the high-pressure stages allows it to regain temperature and thus increases its energy content before it enters the low-pressure stages. This process ensures that the steam remains in a gaseous state, preventing condensation and allowing for a more efficient conversion of heat energy into mechanical energy.

The other options do not serve the purpose of reheating steam in a turbine. Lowering energy output, increasing fuel costs, and enhancing cooling efficiency are not objectives of reheating steam; rather, the intent is to maintain and optimize the energy extraction from the steam while ensuring operational integrity and efficiency.