Physics

Thermal Properties of Matter

302 Questions

Thermal properties of matter examine how substances react to heat, covering concepts like temperature, specific heat, and phase changes. This topic is regularly tested in the physics and general science sections of competitive exams. Use this collection to solve numericals on heat transfer, thermal equilibrium, and melting points.

Heat transfer and mixingMelting and freezing pointsThermal expansion and densityTriple point of waterCarnot cycle applications

Thermal Properties of Matter Questions

Multiple choice

Water has the least volume and maximum density at what temperature?

  1. 0 °C

  2. 4 °C

  3. 100 °C
    • 4 °C

  5. 5 °C
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Generally, all liquids expand on heating but water is an exception to this rule. If water is heated, its volume gradually decreases. (This decrease in volume continues till the temperature rises to 4 °C.) At temperatures over 4 °C water starts expanding. It then keeps expanding with the further rise in temperature, till finally at 100 °C it turns into steam.

Multiple choice

Consider the following statements:

  1. A thermometer indicates 98.6 oC that it may be in a normal person's mouth.
  2. The formation of ice from water is accompanied by absorption of energy as heat.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement 1 is incorrect. A thermometer indicates 98.6 0C that it may be in a cup of hot tea. The normal body temperature of a man is nearly 370 C or 970 F. Statement 2 is correct. The formation of ice from water is accompanied by absorption of energy as heat to break or decrease the number of intermolecular forces.

Multiple choice

Which of the following statements is true with respect to water properties?

  1. The melting and boiling points of water is same and is equal to 100 degree Celsius.

  2. The freezing and melting points of water is same and is equal to 100 degree Celsius.

  3. The freezing and melting points of water is same and is equal to 0 degree Celsius.

  4. The melting, boiling and freezing points of water are all same and is equal to 100 degree Celsius.

  5. The boiling point of water is 100 degree Celsius and freezing point is 0 degree Celsius.

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Boiling point of water = 100 degree Celsius Freezing point of water = 0 degree Celsius Boiling point of water means the temperature at which liquid water starts evaporating to vapour (gas) state. Similarly freezing point is the temperature at which liquid water converts into solid state, i.e. ice. All compounds will have their own melting, boiling and freezing points.

Multiple choice

What is the freezing point of water?

  1. 273* F

  2. 32* F

  3. 100* F

  4. 212* F
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Water freezes at 32°F (0°C) under standard atmospheric pressure. This is the defining point of the Fahrenheit scale, while 212°F is the boiling point. 273°F, 100°F, and 212°F are incorrect values for freezing.

Multiple choice

At high altitudes the boiling point of water decreases because

  1. the atmospheric pressure is high

  2. the temperature is low

  3. the atmospheric pressure is low

  4. the temperature is high
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

At higher altitudes, atmospheric pressure is lower because there's less air above pushing down. Lower pressure means water molecules need less energy to escape into the gas phase, so boiling occurs at a lower temperature.

Multiple choice

The boiling point of water

  1. Is always 100°C

  2. Depends on atmospheric pressure

  3. Depends on the material of the container

  4. Depends on relative humidity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The boiling point of water is 100°C only at standard atmospheric pressure (1 atm or 101.3 kPa). At higher altitudes or lower pressure, water boils at a lower temperature because less energy is needed for water molecules to escape into the gas phase.

Multiple choice

The boillng point of water at sea level is

  1. 32o C

  2. 212o C

  3. 100o C

  4. 98.4o C
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The boiling point of water at sea level is 100°C (212°F). This is when water vapor pressure equals atmospheric pressure. 98.4°F is body temperature, 32°F is freezing, and 212°F is the Fahrenheit equivalent of 100°C, not a separate option. The key is recognizing 100°C as the standard boiling point.

Multiple choice

When air expands on heating, its ___________ .

  1. mass remains the same, but volume increases

  2. volume remains the same, but mass increases

  3. temperature remains the same, but volume increases

  4. mass remains the same, but temperature increases

  5. volume remains the same, but temperature increases
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option. When air expands on heating, its mass remains the same, but volume increases.

Multiple choice

What is the boiling point of pure water?

  1. 97.5 degree Celsius

  2. 100 degree Celsius

  3. 290 degree Celsius

  4. 300 degree Celsius

  5. 100.7 degree Celsius
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is the boiling point of pure water.

Multiple choice

Which of the following colours absorbs heat the most?

  1. Yellow

  2. Black

  3. White

  4. Red
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The color black absorbs all wavelengths of visible light and does not reflect any back to the eye. Because this light energy is converted into thermal energy, black objects heat up much faster than objects of other colors.

Multiple choice

Which of the following correctly describes STP?

  1. 4oC at 1 Atmosphere

  2. 0oC at 1 Atmosphere

  3. 23oC at 1 Atmosphere

  4. 0oC at 0 Atmosphere
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

STP (Standard Temperature and Pressure) is defined as 0 degrees Celsius and 1 atmosphere of pressure.