The emitted or absorbed heat which changes the state of the substance, but does not cause any change in temperature, is called

The emitted or absorbed heat which changes the state of the substance without causing any change in temperature is known as latent heat. This energy is crucial for phase transitions, such as melting, freezing, boiling, or condensation. During these processes, the temperature of the substance remains constant while the latent heat either breaks or forms the molecular bonds necessary for the phase change. For example, when ice melts into water or water boils into steam, the temperature remains stable at the melting or boiling point, respectively, despite continuous heat input. This absorbed or released energy, termed latent heat, is fundamental in understanding various natural and industrial processes involving phase changes. Therefore, the correct answer is [D] Latent heat. This concept is pivotal in fields such as meteorology, refrigeration, and thermal management systems.