Before the year 1900, scientists believed that light and heat (electromagnetic radiation) traveled as a continuous, unbroken wave. However, this theory failed to explain certain phenomena. Enter Max Planck, who changed physics forever with his Quantum Theory.
Core Idea: Energy travels in tiny packets, not as a continuous wave.
Name of packet: Quantum (or Photon for light).
Formula: E = hν.
Inventor: Max Planck (won the Nobel Prize in Physics in 1918).
In 1900, Max Planck proposed a revolutionary idea:
Planck gave the famous mathematical formula for the energy of a quantum:
E = hν
Where:
Planck's quantum theory states that radiant energy is emitted or absorbed not continuously, but in small, discrete packets called 'quanta' or 'photons'. The energy of each quantum is directly proportional to its frequency (E=hν).
Calculate the Heat Supplied for a Complete Cycle — Thermodynamics
For a complete thermodynamic cycle, ΔU = 0, so heat supplied equals work done: Q = W. Use P-V diagram area to find net work done in the cycle.
What are Canal Rays? (Anode Rays)
Learn what Canal Rays (Anode Rays) are in atomic structure. Understand their discovery by Goldstein and their key properties.
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.
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