Here's a breakdown of Planck's quantum formula E = nhν in simple terms:
Imagine Light is Made of Tiny "Energy Packets" (Like Drops of Water)
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Old View:
Scientists thought energy (like light or heat) flowed smoothly, like water from a hose. You could have any amount of energy.
Example: A dimmer switch lets you set light brightness to any level. -
Planck's Discovery (The "Quantum Fix"):
Planck realized energy can't be split infinitely. Instead, it comes in tiny, fixed-size packets called quanta (or photons for light).
Think of it like water being made of individual droplets. You can have 1 drop, 2 drops, 3 drops... but never half a drop.
The Formula: E = nhν
E = Total energy of the light or radiation
n = A whole number (1, 2, 3, ...) — this is the quantum part
h = Planck's constant (a very tiny number, like the size of 1 energy packet)
ν (nu) = Frequency of the light (how fast it vibrates; determines its color or type)
What It Means
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Energy is "Lumpy":
You can only have energy in multiples of hν:
1 packet: E = 1 × hν
2 packets: E = 2 × hν
3 packets: E = 3 × hν
But not 1.5 × hν — no fractions allowed. -
Bigger ν (Frequency) = Bigger Packets:
High-frequency light (like blue light or X-rays) has large energy packets (hν is big)
Low-frequency light (like red light or radio waves) has small energy packets (hν is small) -
h is the "Packet Size" Ruler:
Planck's constant (h) is the smallest possible unit of energy transfer for light. It’s nature’s minimum transaction amount.
Real-World Analogy: Buying Energy "Soda Cans"
Think of energy like soda:
hν = The size of one can of soda
n = The number of cans you buy
E = Total soda you get
You can buy 1 can, 2 cans, 3 cans... but you can't buy half a can
Blue light = Big cans (high ν → large hν)
Red light = Small cans (low ν → small hν)
Why Was This Revolutionary
Planck solved the ultraviolet catastrophe — a big puzzle about hot objects like ovens or stars
His idea started quantum physics: energy isn’t smooth, it’s chunky, like grains of sand
Later, Einstein used this to explain the photoelectric effect — how light kicks electrons out of metal — proving that light acts like particles (photons)
In a nutshell
Planck discovered energy isn’t a smooth flow — it’s delivered in whole-number packets (quanta).
His formula E = nhν says:
Total energy (E) equals a whole number (n) multiplied by the size of one packet (hν)
This tiny fix changed physics forever.
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