Chapter A: Measurement Instruments

The Vernier caliper uses a sliding Vernier scale alongside the main scale. The least count LC = 1 MSD − 1 VSD; standard value is 0.02 mm (50 VSD = 49 MSD). Full reading = MSR + (n × LC). Zero error: positive (Vernier zero right of main scale zero) → subtract from raw reading; negative (Vernier zero left) → add to raw reading. The instrument measures external/internal diameters and depth. The screw gauge measures finer dimensions (LC = 0.01 mm for standard type), and backlash error is prevented by unidirectional rotation. Both instruments have [L] dimensional formula.

Chapter B: Mechanics Experiments (5 experiments)

The simple pendulum: $T^{2}$ vs l graph has slope 4π^{2}/g (effective length = string + bob radius). Young's modulus (Searle's): Y = FL/(A$\Delta L$) in Pa; slope of stress-strain graph in linear region = Y. Surface tension (capillary rise): S = hrρg/(2cosθ) in N/m; for water-glass θ = 0°. Viscosity (Stokes'): terminal velocity v_t = 2$r^{2}$(ρ−σ)g/(9η); three forces balance at v_t. Principle of moments: m_{1}l_{1} = m_{2}l_{2} about the pivot.

Chapter C: Waves & Thermal (2 experiments)

Resonance tube: first resonance at l_{1} + e = λ/4; second at l_{2} + e = 3λ/4. Key formula: v = 2f(l_{2} − l_{1}) — end correction e cancels. Using only l_{1} (v = 4fl_{1}) is inaccurate because the end correction is not eliminated. End correction e = (l_{2} − 3l_{1})/2. Specific heat (method of mixtures): m_{1}c_{1}\Delta$$T_{1} = m_{2}c_{2}\Delta$$T_{2} + m_cal c_cal \Delta$$T_{2}; calorimeter heat capacity must not be neglected.

Chapter D: Electrical Experiments (4 experiments)

Metre bridge (Wheatstone principle): R/S = l/(100 − l); interchange → l' = 100 − l. Resistivity: ρ = RA/L (A = π$d^{2}$/4 from screw gauge). Ohm's law: straight V-I graph (slope = R) for ohmic; curved for non-ohmic. Galvanometer: half-deflection method gives G ≈ S (when S << R); figure of merit k = I/θ (A/div).

Chapter E: Optics Experiments (5 experiments)

Cartesian sign convention governs all optics: real objects have u < 0; concave mirror f < 0; convex mirror f > 0; convex lens f > 0; concave lens f < 0. Concave mirror: 1/v + 1/u = 1/f (u-v method; graph 1/v vs 1/u). Convex mirror: requires auxiliary convex lens (virtual images cannot be screened). Convex lens: 1/v − 1/u = 1/f; 1/v vs 1/u graph intercepts = ±1/f. Prism: μ = sin((A+δ_min)/2)/sin(A/2); i-delta graph is U-shaped; minimum at i = e. Glass slab: μ = real depth/apparent depth (travelling microscope).

Chapter F: Semiconductor Electronics (3 experiments)

p-n junction diode: forward bias — exponential current after V_th (Si: 0.7 V; Ge: 0.3 V); reverse bias — small saturation current until breakdown. Zener diode: sharp reverse breakdown at V_Z; voltage remains constant; used as voltage regulator (always with series resistor). LED: emits light in forward bias; V_th ≈ 1.5–3 V; photon energy = band gap energy = eV_th. Component identification: color code BBROYGBVGW = 0–9 (BB ROY of Great Britain has Very Good Wife).

Key Numbers to Remember

• Vernier LC: 0.02 mm (50-div); Screw gauge LC: 0.01 mm
• Speed of sound formula: v = 2f(l_{2}−l_{1})
• Metre bridge interchange: l' = 100 − l
• Si V_th: 0.7 V; Ge V_th: 0.3 V
• Prism minimum deviation: i = e