How is temperature defined in relation to kinetic energy?

Temperature is fundamentally defined as the average kinetic energy of the particles in a substance. This means that as the temperature of a material increases, the particles move faster on average, indicating greater kinetic energy. For example, in gases, when the temperature increases, particles collide more frequently and with greater energy, which reflects a higher average kinetic energy.

Option A speaks to total energy, which encompasses all forms of energy in a system, not just the kinetic aspect contributing to temperature. Options C and D focus on methods of heat transfer—conduction and convection, respectively—rather than defining temperature itself. Therefore, the definition that best captures the essence of temperature is its relationship to average kinetic energy.