Dimensional Formula of Physical Quantities – Class 11 Physics Yashwant Parihar, February 17, 2026February 17, 2026 The Dimensional Formula of Physical Quantities helps students understand Physics in a simple and logical way instead of memorising formulas. It shows how every physical quantity is connected to basic ideas like length, mass, and time. By learning this topic, students can check formulas, understand relationships between quantities, and feel more confident while solving problems. This chapter makes Physics clearer, easier, and more meaningful for Class 11 learners. What are Physical Quantities? Physical quantities are those quantities that can be measured or expressed in terms of numbers or units. For example, length, mass, time, force, area, etc. There are two types of physical quantities. Fundamental Quantities Physical Quantities Fundamental Quantities Those quantities that can be independent of other quantities are known as fundamental quantities. There are seven types of fundamental quantities. Length Mass Time Temperature Electric Current Amount of Substance Luminous Intensity Derived Quantities Those Quantities which are dependent on fundamental quantities are known as derived quantities. For example, force, work, energy, etc. What is a Dimensional Formula? A Dimensional Formula is an expression of how the quantity depends on fundamental quantities like mass, length and volume. In simple words, a dimensional formula shows the power of the fundamental quantities. The General representation of a dimensional formula is [Q] = Ma Lb Tc. Where, a, b, and c are integers or can be expressed in the form of a fraction All Quantities Dimensional Formula Class 11 (Mechanics) Physical QuantityDimensional FormulaAreaL²VolumeL³DensityM L⁻³VelocityL T⁻¹AccelerationL T⁻²MomentumM L T⁻¹ForceM L T⁻²ImpulseM L T⁻¹Work / EnergyM L² T⁻²PowerM L² T⁻³Pressure / StressM L⁻¹ T⁻²StrainDimensionlessYoung’s ModulusM L⁻¹ T⁻²Modulus of RigidityM L⁻¹ T⁻²Bulk ModulusM L⁻¹ T⁻²Gravitational Constant (G)M⁻¹ L³ T⁻²Angular VelocityT⁻¹Angular AccelerationT⁻²TorqueM L² T⁻²Moment of InertiaM L²Surface TensionM T⁻²Coefficient of ViscosityM L⁻¹ T⁻¹Terminal VelocityL T⁻¹ Properties of Matter & Thermal Physics (Class 11) Physical QuantityDimensional FormulaHeatM L² T⁻²TemperatureK1Heat CapacityM L² T⁻² K1Specific Heat CapacityL² T⁻² K-1Latent HeatL² T⁻²Thermal ConductivityM L T⁻³ K-1Coefficient of Linear ExpansionK-1Stefan’s ConstantM T⁻³ K-4Gas Constant (R)M L² T⁻² K-1 Waves & Oscillations (Class 11) Physical QuantityDimensional FormulaTime PeriodTFrequencyT⁻¹Angular FrequencyT⁻¹Wave VelocityL T⁻¹WavelengthLIntensityM T⁻³ Electrostatics (Class 12) Physical QuantityDimensional FormulaChargeA TElectric CurrentAElectric FieldM L T⁻³ A⁻¹Electric PotentialM L² T⁻³ A⁻¹CapacitanceM⁻¹ L⁻² T⁴ A²PermittivityM⁻¹ L⁻³ T⁴ A²Electric Dipole MomentA T L Current Electricity (Class 12) Physical QuantityDimensional FormulaResistanceM L² T⁻³ A⁻²ResistivityM L³ T⁻³ A⁻²ConductanceM⁻¹ L⁻² T³ A²Current DensityA L⁻²Drift VelocityL T⁻¹EMFM L² T⁻³ A⁻¹ Magnetism & EMI (Class 12) Physical QuantityDimensional FormulaMagnetic FieldM T⁻² A⁻¹Magnetic FluxM L² T⁻² A⁻¹Magnetic MomentA L²PermeabilityM L T⁻² A⁻²InductanceM L² T⁻² A⁻² Optics (Class 12) Physical QuantityDimensional FormulaFocal LengthLPower of LensL⁻¹Refractive IndexDimensionless Modern Physics (Class 12) Physical QuantityDimensional FormulaPlanck’s ConstantM L² T⁻¹Energy of PhotonM L² T⁻²WavelengthLFrequencyT⁻¹Decay ConstantT⁻¹RadioactivityT⁻¹ Why Are Dimensional Formulas Important? Many students feel bored when studying the formulas, but these formulas are important because in boards and competitive exams like JEE and NEET, direct MCQ is asked from these formulas, so students must learn all the dimensional formulas. Also, the dimensional formula is important for: To Check the Correctness of Equations To Derive Relations Between Physical Quantities To Convert Units To Remember Formulas Easily Quick Exam Trick – You have to learn some of the important formulas, like force, energy or charge, so that you can derive other quantities with the help of these quantities. Limitations of Dimensional Formula They cannot determine numerical constants (like 2, π, ½). They cannot distinguish between scalar and vector quantities. They fail for trigonometric, exponential, and logarithmic functions. Physics Class 11 Physics class 11