Key relationship
ΔL=FL/(AY); ε=ΔL/L; σ=F/A.
Physics · Class 11
Compare loaded wires
Mechanical Properties of Solids
A long thin wire stretches more than a short thick wire under the same load. Modulus describes the material; the wire stiffness also depends on its dimensions.
Open the interactive experiment →Compare loaded wires
ஒரே விசையில் நீண்ட மெல்லிய கம்பி அதிகம் நீளும். யங் குணகம் பொருளின் தன்மை; விறைப்பு கம்பியின் அளவையும் பொறுத்தது.
Key notes, relationships and model limits
Remember
A long thin wire stretches more than a short thick wire under the same load. Modulus describes the material; the wire stiffness also depends on its dimensions.
Common trap
A thicker wire need not have a larger Young modulus.
Model limits
Uniform wire, axial tension and constant Young modulus. Keep the resulting stress below the actual material’s elastic limit; no plastic deformation is modeled.
What you will learn
Predict extension and distinguish modulus from structural stiffness.
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
For F=100 N, L=2 m, A=1 mm² and Y=200 GPa, ΔL=200/(10⁻⁶×200×10⁹)=0.001 m.
Why this matters
The model connects compare loaded wires with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
If wire area doubles with other quantities fixed, what happens to extension?
- It doubles
- It halves
- It remains unchanged
Read the explanation
ΔL is inversely proportional to cross-sectional area.
Course connection: Class XI Chapter 8. Consult the roadmap for CBSE, NEET, JEE Main and Advanced scope.