Identify the physical quantity measured by a thermometer.

A thermometer is an instrument used to measure temperature.

$$\boxed{\text{Temperature}}$$

Thermometer W has a narrow range (e.g., $35 \text{ °C}$ to $42 \text{ °C}$) and smaller divisions ($0.1 \text{ °C}$ per mark).
Thermometer X has a wider range (e.g., $-10 \text{ °C}$ to $100 \text{ °C}$) and larger divisions ($1 \text{ °C}$ per mark).
Two differences are:

• The range of temperatures they can measure is different (W is narrow, X is wide).
• The precision or smallest division of their scales is different (W is $0.1 \text{ °C}$, X is $1 \text{ °C}$).

The mercury level in thermometer X is at the $10 \text{ °C}$ mark.

$$\boxed{\text{10 °C}}$$

The formula for converting Celsius to Kelvin is $K = \text{°C} + 273$.

$$K = 10 \text{ °C} + 273$$ $$K = \boxed{\text{283 K}}$$