Key relationship
fn=n/(2L)√(T/µ); T=mg.
Physics · Practical apparatus
Sonometer length and tension
Move sonometer bridges to set vibrating length and change the tension load. Match a tuning-fork frequency to the string resonance; frequency varies inversely with length and as square root of tension.
Open the interactive experiment →Sonometer length and tension
சோனோமீட்டர் அதிர்வெண் நீளத்திற்கு எதிர்விகிதம்; இழுவிசையின் வர்க்கமூலத்திற்கு நேர்விகிதம்.
Key notes, relationships and model limits
Practical tip
Move sonometer bridges to set vibrating length and change the tension load. Match a tuning-fork frequency to the string resonance; frequency varies inversely with length and as square root of tension.
Common trap
Keep tension and linear mass density fixed when testing frequency against inverse vibrating length.
Model limits
uniform stretched wire, fixed endpoints, massless frictionless pulley, small transverse displacement.
What you will learn
Adjust sonometer length and tension apparatus, observe its reading and derive the indicated physical quantity.
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 L=0.5 m, T=9.81 N and µ=1 g/m, f₁≈99.05 Hz.
Why this matters
The model connects sonometer length and tension with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
Quadrupling string tension changes fundamental frequency by?
- A factor of four.
- A factor of two.
- A factor of one half.
Read the explanation
A factor of two.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.