How is specific heat defined in relation to 1 kg of a substance?

Specific heat is defined as the amount of heat required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius (°C). This definition reflects the unique heat capacity of a material, meaning that each substance has a specific heat value that indicates how much energy is needed to increase its temperature.

When 1 kg of a material is subjected to a heat input that results in a temperature increase of 1°C, it demonstrates the specific heat capacity of that material. This essential concept is crucial in thermodynamics, as it helps determine how different substances respond to heat energy and is fundamental for calculations involving energy transfer and thermal management in various applications.

Other choices refer to different scenarios or quantities that do not align with the standard definition of specific heat. For instance, lowering the temperature, raising the temperature over a larger increment, or maintaining constant temperature does not accurately capture the essence of specific heat, which is specifically concerned with the energy required for a 1°C increase in temperature for a mass of 1 kg.