Question

Why is mercury used in glass thermometers?

Options

• It has a very low α value

• It is a solid at room temperature

• It has a high α value, so it expands noticeably with small temperature changes

• It does not expand on heating

Answer 1

It has a high α value, so it expands noticeably with small temperature changes

Explanation:

Mercury has α = 6.1 × 10⁻⁵ K⁻¹, which is much higher than most solids. This large expansion makes temperature changes easy to read on a scale.