Temperature and Its Measurement: 16 MCQs with answers

Average kinetic energy of the particles of a body

Temperature measures the average kinetic energy of the particles, not the total heat energy. Heat energy also depends on mass and material.

Joule

Heat is energy transferred due to a temperature difference, and its SI unit is the joule (J). Kelvin, Celsius, and Fahrenheit are temperature scales.

$32\,^\circ\text{F}$

The ice point is $0\,^\circ\text{C} = 32\,^\circ\text{F} = 273.15\,\text{K}$. The steam point is $212\,^\circ\text{F}$.

To prevent mercury from flowing back into the bulb

The kink (constriction) stops mercury from returning to the bulb, so the reading is held until the thermometer is shaken down.

Kelvin

The Kelvin scale starts at absolute zero ($0\,\text{K} = -273.15\,^\circ\text{C}$), the lowest possible temperature.

True

**Heat** and **temperature** are different quantities: heat is energy (measured in joules) while temperature is a measure of hotness (measured in °C, °F, or K).

Metal conducts heat away from your hand faster

Both are at the same temperature. Metal feels colder because it conducts heat away from your hand faster than wood does.

$310.15\,\text{K}$

Using $K = C + 273.15$, we get $K = 37 + 273.15 = 310.15\,\text{K}$.

Thermal equilibrium

Thermal equilibrium is the state when two bodies in contact reach the same temperature, and net heat flow stops.

The volume of mercury in a glass tube

A thermometric property changes predictably with temperature. The volume of mercury is a classic example, as is the resistance of a thermistor.

Radiation

Radiation transfers heat via electromagnetic waves and needs no medium, which is why heat from the Sun can cross the vacuum of space.

It carries very little heat energy due to its tiny mass

Heat energy depends on mass as well as temperature ($Q = mc\Delta T$). The spark's mass is so tiny that it carries very little heat despite its high temperature.

1 kg of water needs 4200 J to rise by 1 K

Specific heat capacity is the heat needed to raise the temperature of 1 kg of a substance by 1 K. For water, this is about 4200 J.

They are easily reproducible fixed points at standard pressure

The ice point ($0\,^\circ\text{C}$) and steam point ($100\,^\circ\text{C}$) are easily reproducible at standard pressure, making them reliable reference points for calibration.

Conduction and convection

A vacuum prevents conduction and convection because both need particles. Radiation is reduced separately by the silvered walls.

A is in thermal equilibrium with C

This is the zeroth law of thermodynamics: if A is in equilibrium with B and B with C, then A is in equilibrium with C.