5.25 calories are absorbed by an iron nail. how many joules is this?
1.07
9.43
12.6
21.9

21.9 joules

Explanation:

Given: The amount of calories absorbed by an iron nail = 5.25

We know that 1 kilocalories =4184 joules

Using unitary method,

Now, to convert 5.25 calories into joules , multiply 5.25 by 4.18, we get

i think the answer is b.