Physics · Class 11

Heat a solid, liquid and ideal gas

Heating expands most materials, but coefficients and constraints matter. A solid’s volume coefficient is roughly three times its linear coefficient; a liquid has its own volume coefficient. A constant-pressure ideal gas volume follows absolute temperature.

Open the interactive experiment →

Heat a solid, liquid and ideal gas

திடப் பொருளின் நீள விரிவாக்கம் αLΔT; திரவத்தின் அளவு விரிவாக்கம் βVΔT. நிலையான அழுத்தத்தில் வாயுவின் அளவு கெல்வின் வெப்பநிலைக்கு நேர்விகிதம்.

Key notes, relationships and model limits

Key relationship

ΔL=αL₀ΔT; solid ΔV/V≈3αΔT; liquid ΔV=βV₀ΔT; ideal gas at fixed p: ΔV/V₀=ΔT/T₀.

Remember

Common trap

Liquid volumetric expansion cannot be obtained by tripling an unrelated solid’s linear coefficient.

Model limits

Small isotropic solid expansion, liquid with its own constant volumetric coefficient, and a separate ideal gas at constant pressure. The liquid does not undergo a phase change; no container expansion is included.

What you will learn

Compare solid, liquid and gas expansion and use absolute temperature for gases.

Try the experiment

Try both scenarios, change one control, and predict the result before checking the graph and readouts.

Think of it this way

Change one input while keeping the others fixed, as you would in a controlled experiment.

Worked example

The rod expands 1.2 mm. One litre of liquid with β=200×10⁻⁶/K expands by 20 mL for a 100 K rise. A 300 K ideal gas warmed 100 K at fixed pressure expands by 1/3.

Why this matters

The model connects heat a solid, liquid and ideal gas with an observable reading. Check the equation and assumptions before applying it.

Before you start

SI units · algebra · graph reading

Check your understanding

How much does a 1 m rod expand for α=12×10⁻⁶/K and ΔT=100 K?

0.012 m
0.0012 m
0.00012 m

Read the explanation

ΔL=αL₀ΔT=12×10⁻⁶×1×100.

Course connection: Class XI Chapter 10. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.