## Post Module #25

Lianna Kishi 1A
Posts: 23
Joined: Thu Jul 27, 2017 3:00 am

### Post Module #25

Can someone help me with this question and explain the answer? I thought the answer would be C but it's wrong.
25. Photoelectric experiments gave rise to a new equation relating the energy of light to its frequency. Select the right equation.
a) $\lambda \nu =c$
b) $E_{k}= mv^{2}/2$
c) $mv^{2}/2= hv-\varphi$
d) E= $h\nu$
e) None of the above.

Thanks!

Ryan Sydney Beyer 2B
Posts: 82
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: Post Module #25

The correct answer is D for this question. The results of the photoelectric experiments came as a surprise to scientists because light was not acting like a typical wave in that when intensity was increased, energy was increased. Instead the photoelectric experiments showed that when the frequency of light was increased, then the energy of the light was increased. This core finding from the set of experiments is at the heart of the equation $E = h\nu$

Matthew Lee 3L
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am

### Re: Post Module #25

I agree with Ryan on this one. They found out that the frequency of light affected the energy rather than the intensity, which just increased the number of photons in the beam of light. If you look at the E=hv equation, you can see that as frequency goes up, so does energy. Since h is just a constant, the only thing affecting energy is the frequency which has a positive relationship with energy.