NEET · Physics
Cover official NEET UG 2026 Physics Unit 20, Experimental Skills: the listed experiments and activities, the instrument readings they need, and the graph and error reasoning behind them.
In short
Experimental Skills is Unit 20 of the official NEET UG 2026 Physics syllabus. It asks for familiarity with the basic approach and observations of 18 listed experiments and activities, from Vernier callipers and the screw gauge to diode and Zener characteristic curves. The skill being tested is reading an instrument correctly, knowing what is measured and why, and interpreting the resulting graph or reading.
Subject faculty
Also in Physics: Kumar Gandharva Saxena
Listed in official order. Each row names the chapter page that explains the underlying physics.
Activity wording follows the official NEET (UG) 2026 syllabus. Related pages are Rank Sarthi study links, not official groupings.
For Vernier callipers, least count = value of one main-scale division − value of one Vernier-scale division. For the screw gauge, least count = pitch ÷ number of circular-scale divisions. A reading is main-scale reading + (coinciding division × least count), corrected for zero error. Report no more decimal places than the least count supports.
If the zero of the Vernier or circular scale sits ahead of the reference with jaws closed, the zero error is positive and must be subtracted from every reading. If it sits behind, the error is negative and subtracting it adds to the reading. Correct reading = observed reading − zero error.
Several activities are defined by a graph: amplitude squared against time for the pendulum, angle of deviation against angle of incidence for the prism, and current against voltage for the p-n junction and Zener diodes. Read what the slope, minimum or turning point means physically before using any number from the graph. For the prism, the minimum of the curve is the angle of minimum deviation.
Most activities measure simple quantities (length, time, mass, temperature, current, voltage) and then derive the target: Young's modulus from load and extension, viscosity from terminal velocity, resistivity from a balance length, specific heat from a heat balance. The largest fractional error in the measured quantities, especially those raised to a power, usually dominates the error in the derived result.
In the identification activity, a resistor conducts equally in both directions, a diode conducts in one direction only, an LED conducts in one direction and emits light, and a capacitor shows a momentary current that then falls to zero under a steady voltage.
Least count of Vernier callipers equals one main-scale division minus one Vernier-scale division.
Least count of Vernier callipers
Use when — Use the value of one main-scale division and one Vernier-scale division in the same unit.
Least count of a screw gauge equals pitch divided by the number of circular-scale divisions.
Least count of a screw gauge
Use when — N is the number of divisions on the circular scale; pitch is the linear advance per full rotation.
Young's modulus equals load times original length divided by cross-sectional area times extension.
Young's modulus of a wire
Use when — Within the elastic limit. A = πr², so the error in radius counts twice.
Viscosity equals two r squared times density difference times g, divided by nine times terminal velocity.
Viscosity from terminal velocity (Stokes' law)
Use when — Small sphere at terminal velocity in a viscous liquid; ρ is the sphere density and σ the liquid density.
At balance, R over S equals l over one hundred minus l.
Metre bridge balance condition
Use when — At the null point, with l in centimetres measured from the end next to R.
Adding a negative zero error instead of subtracting it
Execution errorWhy it happens
Preparation Intelligence classification: Execution Error.
How it is corrected
Always apply correct reading = observed reading − zero error, keeping the sign of the zero error.
Reading the prism graph's end points instead of its minimum
Knowledge gapWhy it happens
Preparation Intelligence classification: Knowledge Gap.
How it is corrected
The angle of minimum deviation is the lowest point of the deviation against incidence curve.
Treating the Zener breakdown region as forward bias
Knowledge gapWhy it happens
Preparation Intelligence classification: Knowledge Gap.
How it is corrected
Zener breakdown is a reverse-bias effect; the sharp current rise appears on the negative-voltage side of the curve.
FAQ
Straight answers about how Rank Sarthi fits into serious exam preparation.
Yes. It is Unit 20 of the official NEET UG 2026 Physics syllabus.
Eighteen experiments and activities, shown in official order on this page.
No. Rank Sarthi does not publish weightage or question-count claims without a verified dataset.
Activity scope is taken from the official NEET (UG) 2026 syllabus. No performance, weightage or question-frequency data is asserted.
