## HW help

$c=\lambda v$

405404782 Gabriel Rigole 4F
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### HW help

Sorry for asking, but how would start and or look at problems 1A 7, and 1B 3 ?

Chem_Mod
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### Re: HW help

For 1A.7, if you recall, for any wave model the product of the frequency and wavelength equals a constant. For the wave model of light, the relationship is frequency (in Hz) x wavelength (in m) = speed of light (~3.00x10^8 m/s). You will have a better understanding of how to answer 1b.3 after Monday's lecture.

Megan Vu 1J
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Joined: Thu Jul 25, 2019 12:15 am

### Re: HW help

In 1A 7, we know the equation c = λV for speed of light (3.00 x 10^8 m*s^-1) = wavelength times frequency. This must be changed to λ = c/V in order to find the wavelength, and this equals to 3.00 x 10^8 m*s^-1 / 7.1 x 10^14 s^-1. This would in turn equal to 4.2 x 10^-7 m or converted to nm as 420 nm. You would use the same procedure for part b of 1A 7.

In 1B 3, this forms the fundamental idea that electromagnetic radiation has properties of particles. According to the lecture, it is evident that photoelectric effect is most reasonable because this experiment showed how shining light on metal surfaces can measure the energy needed to remove electrons from different metals. This displays light as packets of photons, showing the energy per photon as E = hV.