Question

When a metal rod is heated it expands because :

• A. The size of its atoms increases.
• B. The distance among its atoms increases.
• C. Atmospheric air rushes into it.
• D. The actual cause is still unknown.

Answer 1

The correct option is B The distance among its atoms increases.

When a metal rod is heated it expands because its atoms start moving faster, “vibrating”. As they vibrate, they push nearby atoms a little more than they used to do, pretty much using more space than they usually do.

Hence the distance among its atoms increases.