J is the same amount of energy as _ A) 155 cal B) 2720 cal C) 650. cal D) 1550 cal E) 2.72 cal
The Correct Answer and Explanation is:
The correct answer is A) 155 cal.
Explanation:
The relationship between joules (J) and calories (cal) is based on the conversion factor: 1 cal=4.184 J1 \, \text{cal} = 4.184 \, \text{J}1cal=4.184J
To convert 650 joules (J) into calories, we use the formula: Calories=Joules4.184\text{Calories} = \frac{\text{Joules}}{4.184}Calories=4.184Joules
Substituting the given value of 650 J: Calories=6504.184≈155.1 cal\text{Calories} = \frac{650}{4.184} \approx 155.1 \, \text{cal}Calories=4.184650≈155.1cal
Thus, 650 J is approximately equal to 155 calories.
Why this is true:
The joule (J) is the SI (International System of Units) unit of energy, and the calorie (cal) is a non-SI unit often used in the context of food energy. To understand this conversion, think of joules as a more universal unit used in scientific contexts, while calories are still common in food science and other practical areas.
By using the above conversion factor, we can determine that 650 J is nearly the same as 155 calories, which aligns with the answer choice A. It’s important to note that calories in this context are not the “large calories” (kcal) used on food labels, but the small calories, which are sometimes referred to as “gram calories” or “small calories.”
