type: mnemonic_note | topic: all-experiments-mnemonics

1. Zero Error Correction: PS-NA

"Positive → Subtract, Negative → Add"

• Positive zero error = vernier zero to the Right = reads more = Subtract it.
• Negative zero error = vernier zero to the Left = reads less = Add it.
• Alternate: "Plus Sub, Negative Add" — PS-NA.

2. Resonance Tube: "Twelve Eliminates End"

v = 2f(l_{2}−l_{1}) — "TWO" lengths "ELIMINATE" the "END" correction.

• Never use just ONE length (v = 4fl_{1} includes end correction).

3. Si vs Ge: "Silicon Seven, Germanium Three"

• Si: 0.7 V (seven-tenths), Ge: 0.3 V (three-tenths).
• Silicon > Germanium for threshold voltage (wider band gap).

4. Resistor Color Code: "BB ROY of Great Britain has Very Good Wife"

• Black(0) Brown(1) Red(2) Orange(3) Yellow(4) Green(5) Blue(6) Violet(7) Grey(8) White(9)
• Tolerance: Gold = ±5%, Silver = ±10%, None = ±20%.

5. Simple Pendulum: "T squared, L straight"

• $T^{2}$ vs l is a straight line through the origin.
• NOT T vs l (parabola) and NOT T vs $l^{2}$ (wrong relationship).

6. Prism Minimum Deviation: "i equals e for minimum"

• At δ_min: angle of incidence i = e (angle of emergence).
• The ray is symmetric; it travels parallel to the base inside the prism.

7. Sign Convention: "Real is Negative, Virtual is Positive" (for mirrors)

• For a real image in a concave mirror: v is negative (image in front of mirror).
• For a virtual image: v is positive (image behind mirror).

8. Metre Bridge Interchange: "One minus l"

• Interchange R and S → new balance at l' = 100 − l (mirror about 50 cm).

9. Capillary Rise: "Narrower goes Higher" (h ∝ 1/r)

• Narrower tube (smaller r) → greater rise h = 2S cosθ/(rρg).

10. Young's Modulus Memory: "Stress over Strain in the linear lane"

• Y = stress/strain, valid only in the proportionality (linear) region of the stress-strain curve.