High School Physics : Understanding Photons

Study concepts, example questions & explanations for High School Physics

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Example Questions

Example Question #1 : Light And Electromagnetic Waves

Why is it that photons can move at the speed of light, but other particles cannot?

Possible Answers:

Photons are similar in size to electrons

Photons do not have mass

Photons contain more energy than other particles

Photons lack electrical charge

Correct answer:

Photons do not have mass


Photons can move at the speed of light because they have no mass. Anything with mass can not be accelerated to the speed of light—it takes an infinite amount of energy to do so. We can get very close, but never exactly there.

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