Why does light have momentum but no mass?|Sarim Khan

[noyou]

Sarim ji pls make video on kepler laws in too detail pls (for jee advance)

[rudraprataprathour]

Light, being a form of electromagnetic radiation, exhibits both wave-like and particle-like properties (wave-particle duality). This unique nature leads to:

*Momentum without Mass*

According to special relativity and quantum mechanics:

1. *Mass*: Light has zero rest mass (m0 = 0), meaning it doesn't resist changes in its motion like particles with mass do.
2. *Momentum*: Light carries momentum (p) due to its energy (E) and speed (c):

p = E / c

This momentum arises from the photon's energy, not from any mass.

*Why momentum without mass?*

1. *Photons*: Light is composed of massless particles called photons. Photons have energy and momentum but no mass.
2. *Relativistic effects*: Special relativity shows that energy (E) and momentum (p) are related by:

E² = (pc)^2 + (m0c^2)^2

For massless particles like photons, m0 = 0, simplifying the equation to:

E = pc

This means energy and momentum are directly proportional.
1. *Quantum field theory*: Light's momentum arises from the quantization of electromagnetic fields.

*Consequences*

1. *Radiation pressure*: Light's momentum transfer can exert pressure on surfaces.
2. *Solar sails*: Spacecraft can harness light's momentum for propulsion.
3. *Optical comms*: Light's momentum enables optical communication systems.

*Key takeaways*

- Light's momentum stems from its energy, not mass.
- Massless particles like photons can carry momentum.
- Wave-particle duality and relativistic effects explain this phenomenon.

Would you like more details on light's properties or quantum mechanics?

[srinjoydas]

If we consider the causality, force is "CAUSE" of acceleration and mass is "RESISTANCE" to such acceleration. Now let's consider what is momentum, so in all it's simplicity if something pushes a thing and makes it move then we can say that, that "something" has momentum. let's consider an electron in the way of light then the electric field moves the electron up and down thus enables the magnetic field to push that electron(why you say electric field is the homie of magnetic field without electric field the "motion of charge" cannot happen. So, hooray! light has momentum but very small at that.

Edit: Fun fact! mass does not exist but energy does(that we perceive as mass) *DOOM Music and Vsauce Music plays in*

[Unknownn]

I have a question if we say we apply force on an object to move it but it doesn't move then where does that energy go will energy be conserved here?

[_aaditya]

Sarim can you please make a one shot video for kinematics. I am also in 10th

[krishnakawale]

Bro how are you able to solve jee advanced questions can you please guide me...

[MaazAhmad_]

Sir I am requesting you from my heart 🤕
Plz tell me why we represent light as ray??? 😭😥 explain this doubt.
I have seen most of teacher while teaching lenses.say light ray is entering in lens but light ray is path of light.how can we represent light by its path.

[ParvezKhan-qlmg]

Superb, really I am a PGT commerce teacher, bhut accha concept clear kar rhe ho beta,

[Haleem-IITB]

You got a new subscriber buddy, keep it up. Dont get demotivated by haters, they just carry bundles of insecurity.with no intellect..

[umrayaseen]

Mashallah brother keep it up🎉 you had a really great talent you should try in inpho or Olympiad of physics you should definitely select in it by the way i am in 11 jee aspirant

[SudeepKumar-rlgc]

light gets its momentum by its magnetic feild

[MahtabAlam-oy]

Bhai class 10th ka physics padhawo na mai bhi class 10 th me hu aur aap to jiyadah hi higher level ka padhate hai

[raunakyadav]

Bhai tu inpho ka paper do india ke liye gold laoo

[nurehera]

Mashaallah bhai❤ u are really Einstein