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Question
Hello sir

Sir i just want to know that we have eyes but without light we can't see with eyes then if light is not there if we just imagine then we can't see. Then how this statement is true which is thought for us when are in 2nd standard i.e eyes help us to see.

Sir please explain this also clearly and in lucid and esay way.

Answer
Seeing is a physical process involving a chemical reaction and change in our eyes due to the light, which is then converted by our cells into electrical signals.  These signals are then interpreted in the brain.  The particles of light (photons) must be absorbed to cause this process to happen.  Therefore, without light we cannot see.

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Dr. Stephen O. Nelson

Expertise

I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

Experience

I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Education/Credentials
Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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