Question

When an iron nail is ground into powder, its mass ____.

Answer 1

Explanation:

(a) The mass of an object remains the same always. It is independent of its location. In this case, an iron nail is ground into powder. It means that its mass will remain unchanged. Hence, (a) is the correct option.

(b) Whenever there is a change of color of an object, a chemical reaction occurs. It shows that a reaction happens there. In this problem, a paper turns yellow-brown upon exposure to sunlight. A chemical reaction takes place there. Hence, (b) is the correct option.