Planck's constant (denoted by h) is a fundamental physical constant in quantum mechanics. Deriving its dimensional formula is a frequent question in Class 11 Physics.
Max Planck introduced this constant in 1900 to describe the quantization of energy, laying the foundation for all of quantum physics.
Planck's constant relates the energy of a photon to its frequency, according to the equation:
E = hν (Where E = Energy, h = Planck's constant, ν = frequency)
Therefore: h = E / ν
Dimension of Energy (E): Energy = Work = Force × Distance E = [M L T⁻²] × [L] = [M L² T⁻²]
Dimension of Frequency (ν): Frequency = 1 / Time period ν = [T⁻¹]
Dimension of Planck's Constant (h): h = [E] / [ν] h = [M L² T⁻²] / [T⁻¹] h = [M L² T⁻²⁺¹] h = [M¹ L² T⁻¹]
Note: The dimensional formula of Planck's constant [M L² T⁻¹] is exactly the same as that of Angular Momentum.
No, Planck's constant has dimensions [M L² T⁻¹] and units (Joule-second). Dimensionless constants include pure numbers like π or refractive index.
Can a Substance Contract on Heating? — Yes, Water Does
Yes, water contracts on heating from 0°C to 4°C — called anomalous expansion of water. Maximum density at 4°C = 1000 kg/m³. Full explanation with examples.
A Capacitor of Capacitance C Charged to V₀ Potential
A capacitor of capacitance C charged to V₀: charge Q = CV₀, energy stored U = ½CV₀². Two-capacitor problems, energy loss, Class 12 Physics explained.
What Happens When a Ceiling Fan is Switched Off?
When a ceiling fan is switched off, it decelerates gradually due to friction torque. Angular velocity decreases over time — Newton's first law of rotation and angular deceleration explained.
What is Centre of Curvature?
Learn the definition of centre of curvature for spherical mirrors. Understand its relationship with the radius of curvature and pole.
What is the CGS Unit of Force?
Learn the CGS unit of force (Dyne). Understand the difference between the CGS and SI systems, and how to convert Dynes to Newtons (1 N = 10^5 dynes).
Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.