So if you're not in this 77%, let's quickly go over why, in fact, this is the correct answer, . 9 times 10 to the negative 18 joules.

如果你们不在这77%中，让我们快速的来看一看为什么，这个是正确答案，0，9乘以10的负18次方焦耳。

麻省理工公开课 - 化学原理课程节选

Now, your temptation is to keep the first answer because you know energy is not going to be negative.

你肯定想保留正根,因为你知道能量不会是负值

耶鲁公开课 - 基础物理课程节选