$1\,J =$ ............ $\text{calorie}$. (Fill in the blank)

(0.239) The relationship between Joule $(J)$ and calorie $(\text{cal})$ is defined by the mechanical equivalent of heat.
$1 \text{ calorie} = 4.184 \text{ J}$.
Therefore, $1 \text{ J} = \frac{1}{4.184} \text{ calorie}$.
$1 \text{ J} \approx 0.239 \text{ calorie}$.