## 1B.15 help w/ part c

$E=hv$

Mallika Singh 1G
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Joined: Sat Aug 24, 2019 12:16 am

### 1B.15 help w/ part c

I was just wondering why we had to use that kinetic energy formula instead of being able to convert using the simple einstein equation. What am I missing here?

Chem_Mod
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### Re: 1B.15 help w/ part c

The Einstein equation is only used to find the energy of electromagnetic radiation. For particles like electrons, you have to find their kinetic energy using 1/2 mv^2.

VPatankar_2L
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### Re: 1B.15 help w/ part c

For this question, you have to remember the equation: E photon - work function = Kinetic Energy (of electron). In this situation, the E=hv equation applies to the photon and finding the energy of the photon. But to find the energy of the emitted electron, you need to use KE=(1/2)m(v)^2.