Light: Light has photons as particles but travels like a wave so it shows the dual characteristics. Meaning it can show both characteristic...

**Light:**

Light has photons as particles but travels like a wave so it shows the dual characteristics. Meaning it can show both characteristics of being a particle as well as a wave.

Light is made up of
*Photons*:

**Photons:**

They are basically a packet of energy.

They are also the quantum (as in the very basics) of electromagnetic energy.

Just a random fact: The most energetic photons are Y-ray also known as gamma-ray photons.

**Einstein's Equation:**

When it comes to light, the equation we have to know is:

E = hf also known as Einstein's Equation

here,

E is the energy of Photons calculated in Joule in short J

h is the Plank’s constant which is equal to 6.63 * 10 ^-34 Joules per second

Now, the energy of photons are directly proportional to the frequency of electromagnetic radiation, So;

E is directly proportional to f ---- equation I

Also the equation for speed is: c = f * Î»

f = c / Î» ----- equation II

Now,

E = hf

E = h (c /Î») {from the equation I and II}

This tells us that, less the wavelength more the energy.

Example: X-ray has short-wavelength so it is more energetic in comparison to visible light.

**The Electron Volt
(eV):**

Formula: W = Q.V

1 Ev is energy transferred when 1 electron travels through the potential difference of 1 Volt.

1eV = 1.60 * 10^-19 J

Likewise, if 5 electrons were to move through a potential difference of 10 volts 50 eV energy is transferred.

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