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units for energy

Posted: Wed Dec 04, 2019 8:23 pm
by Elyssa Smith 4B
What are the units for energy in the E=hv equation? Is it Joules or Joules/photon?

Re: units for energy

Posted: Wed Dec 04, 2019 8:47 pm
by Anika Chakrabarti 1A
The unit is J, but in the E=hv equation you are finding the energy of a photon, so technically this value means the amount of energy per photon. I think you can just write J in your answer though.

Re: units for energy

Posted: Thu Dec 05, 2019 2:23 pm
by Jared Khoo 1G
The unit for energy is Joules, which is equivalent to a Newton*meter. Planck's constant h is in the units of m2kgs-1 and the unit for v frequency v is s-1. Multiplying these together you would get m2kgs-2. As a newton is in the units of kgms-2, you can see that this equation indeed does find Joules, or N*m.