Key relationship
I=E/(Rrheostat+rL); V(x)=Irx; gradient=Ir.
Physics · Practical apparatus
Wire probe potential gradient
Move the probe along the same wire and compare potential drop with distance. Uniform resistance per length gives a straight-line voltage gradient. The rheostat changes current and therefore the gradient.
Open the interactive experiment →Wire probe potential gradient
ஒரே கம்பியில் சோதனைத் தொடுப்பை நகர்த்தும்போது மின்னழுத்த வீழ்ச்சி நீளத்துடன் நேராக அதிகரிக்கும்.
Key notes, relationships and model limits
Practical tip
Move the probe along the same wire and compare potential drop with distance. Uniform resistance per length gives a straight-line voltage gradient. The rheostat changes current and therefore the gradient.
Common trap
The wire voltage need not equal the full supply when a series rheostat is present.
Model limits
Uniform wire with constant resistivity and cross-section; ideal high-resistance voltmeter and steady source. Heating omitted.
What you will learn
Measure a potential gradient with a virtual sliding probe.
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
6 V,4 Ω rheostat and2 Ω wire gives1 A; halfway drop is1 V.
Why this matters
The model connects wire probe potential gradient with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
For a uniform wire at steady current, V(x) is?
- Proportional to x²
- Proportional to x
- Independent of x
Read the explanation
Each equal length contributes the same resistance and voltage drop.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.