\( \frac{\text { thermal capacity of a sample of copper }}{\text { specific heat capacity of copper }} \) A. does not have any unit. B. has unit \( \mathrm{J} \mathrm{kg}^{-1} \mathrm{~K}^{-1} \). C. has unit \( \mathrm{J} \mathrm{kg}^{-1} \). D. has unit kg .

The thermal capacity of a sample of copper is given by the formula: \[ \text{Thermal capacity} = \text{Specific heat capacity of copper} \times \text{Mass of copper} \] The specific heat capacity of copper is measured in \( \text{J} \, \text{kg}^{-1} \, \text{K}^{-1} \). Therefore, the unit of the thermal capacity of a sample of copper is \( \text{J} \, \text{kg}^{-1} \). So, the correct answer is B. The unit of the thermal capacity of a sample of copper is \( \text{J} \, \text{kg}^{-1} \, \text{K}^{-1} \).