Does Light Have Mass or Is It Just Energy?

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    Light Mass Photovoltaic
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SUMMARY

The discussion centers on the nature of light, specifically whether it possesses mass or is purely energy. The student argues that light must have mass due to its ability to change momentum and be affected by gravity, referencing the uncertainty principle. The teacher counters that light is energy until it interacts with matter, at which point it can exhibit mass-like properties. This exchange highlights the complexities of understanding light's dual nature as both a wave and a particle.

PREREQUISITES
  • Understanding of the photoelectric effect
  • Familiarity with the uncertainty principle in quantum mechanics
  • Basic knowledge of momentum and its relation to mass
  • Concept of gravitational effects on light
NEXT STEPS
  • Research the photoelectric effect and its implications on light behavior
  • Study the uncertainty principle in detail, focusing on its applications in quantum physics
  • Explore the concept of light as both a wave and a particle (wave-particle duality)
  • Investigate gravitational lensing and its effects on light propagation
USEFUL FOR

Students of physics, educators, and anyone interested in the fundamental properties of light and its interactions with matter.

David_Harkin
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I am a lower sixth student and i got into an argument with my physics teacher today when we were talking about the photovoltec effect and he said that light has no mass. I have a very small understanding of the subject compared to him but from what i do understand the uncertainty principle states that light can change the momenteum of something and so it must have mass to have momentium. Also i know that gravity can bend light and this also points out that it must have a mass. His response was that light is just energy until it hits something and then it changes its energy to mass.
I cannot grasp the concept of something existing of pure energy i was wondering if somebody could shed some light on this. Thanks
 
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I recall a new addition to the FAQ regarding this a few days ago. Here's the link: https://www.physicsforums.com/showpost.php?p=1285138&postcount=6
 
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Thanks, i understand it now.
 

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