Build a grouped memory table covering all 9 major dimensional families Memorise the 9 core groups from [M⁰L⁰T⁰] to [ML²T⁻²θ⁻¹], associating each with its member quantities. Verify each by deriving from defining equations (pressure = force/area = [M¹L¹T⁻²]/[L²] = [M¹L⁻¹T⁻²]). The trap: confusing torque [M¹L²T⁻²] with angular momentum [M¹L²T⁻¹] because the T exponent differs by 1. Recognise this topic when NEET lists pairs from different chapters and asks which matches dimensionally.

Drill the dimensionless [M⁰L⁰T⁰] group as an elimination shortcut Memorise that strain, refractive index, relative density, dielectric constant, Poisson’s ratio, angle, and solid angle are all dimensionless. If one option pairs a dimensionless quantity with a dimensional one, eliminate it instantly. The condition: the quantity must be a pure ratio. The trap: treating relative permittivity as having the dimensions of permittivity ε₀ — the word relative signals a dimensionless ratio.

Link electrical and mechanical energy expressions through [M¹L²T⁻²] Memorise that I²Rt, V²t/R, VIt, qV, LI², q²/C, and CV² all reduce to [M¹L²T⁻²]. Verify by substituting SI base units for each electrical quantity. The trap: assuming LI² differs from qV because the energy formula has a factor of ½ — numerical prefactors never affect dimensional analysis. Spot this when NEET mixes electrical and mechanical quantities in options.

Derive unfamiliar quantities from their defining equations When NEET introduces a quantity outside your table (coefficient of viscosity η, Stefan’s constant σ), derive from the defining equation: F = ηA(dv/dx) gives η = [ML⁻¹T⁻¹]. The condition: identify the defining formula from the question. The trap: guessing by name analogy — confusing gravitational potential [M⁰L²T⁻²] with gravitational PE [M¹L²T⁻²] where mass is absent in the per-unit-mass version.