How Can Photons Have Energy Without Mass?

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In summary, Timon and Pumba are discussing why photons have no mass at rest but still have properties such as energy and momentum. Timon suggests that this is because the energy of a photon is equal to its mass times the speed of light squared, and if mass is 0, then energy and momentum would also be 0. Pumba argues that this is not true and that energy and momentum are related in a different way for particles with 0 mass. McQueen wonders if this means that energy must have mass, but Timon and Pumba explain that momentum, not mass, is what relates to energy for photons.
  • #1
ddr
Timon, Timon, I wonder howcome photons have no mass at rest and yet mass is their only property?
Pumba, Pumba, you wonder - I know. There are no photons at rest!
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ha, ha, ha...ain't it funny?
 
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  • #2
mass is their only property?

What do mean by that? Photons have energy, travel at the speed of light, have spin 1, and other properties.
 
  • #3
it is because...

the energy of the photon is E=mcc
the momentum p=mc
...
---------------------------
if m=0 (there is no m) then
E=0;p=0... too(there is no E,p...).
 
  • #4


Originally posted by ddr
the energy of the photon is E=mcc
the momentum p=mc
...
---------------------------
if m=0 (there is no m) then
E=0;p=0... too(there is no E,p...).

Doesn't work that way.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html

If mass is 0, than energy is equal to momentum times c.

Think relativistically!
 
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  • #5


Originally posted by neutroncount
If mass is 0, than energy is equal to momentum times c.
Ok, how much is the momentum then?
 
  • #6
Obviously then the photon must have mass ,right ? And if we follow this statement through to its conclusion it means that energy must have mass ?
 
  • #7
Originally posted by McQueen
Obviously then the photon must have mass ,right ? And if we follow this statement through to its conclusion it means that energy must have mass ?

Why must a photon has mass? Look at the equations again. Energy approximately equates to momentum with a zero rest mass particle (mass disappears at c/c in the equation). So its MOMENTUM that relates to energy with the photon, not mass.
 

FAQ: How Can Photons Have Energy Without Mass?

What is the concept behind "Timon and Pumba on photons"?

The concept behind "Timon and Pumba on photons" is to use the beloved characters from Disney's The Lion King to teach children about the properties and behavior of photons, which are the fundamental particles of light.

How do Timon and Pumba explain the properties of photons?

Timon and Pumba use fun and relatable examples from their adventures to explain the properties of photons, such as how they can travel through different materials and how they can be absorbed or reflected by objects.

Is "Timon and Pumba on photons" scientifically accurate?

Yes, "Timon and Pumba on photons" is scientifically accurate. The information presented about photons is based on current scientific knowledge and is presented in a fun and engaging way for children to understand.

What age range is "Timon and Pumba on photons" appropriate for?

"Timon and Pumba on photons" is appropriate for children ages 5-10. However, older children and even adults may also enjoy the educational content presented in the story.

Can "Timon and Pumba on photons" be used in a classroom setting?

Yes, "Timon and Pumba on photons" can be used in a classroom setting as a supplemental resource for teaching about photons and light. It can also be used as a fun and interactive way to engage students in science education.

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