Planck and Wave Theory

Answer choices

1. A

   Wrong Emphasis2% picked this

   If classical wave theorists had never focused on blackbody radiation, Planck’s insights would not have developed and the stage would not

   The main clause of this answer is "Planck's insights would not have developed and the stage would not have been set for Einstein". Why would we say the main point was talking about some counterfactual world? Wasn't the passage trying to tell a story about the actual world? When we say, "If hadn't been for X, Y would have never happened", we're making X seem crucial and important. So we could hear this answer choice saying, "Classical wave theorists were super crucial and important to focus on blackbody radiation!" That's definitely the wrong emphasis. The main character of this passage is Planck or the its the new conception of radiation as clicky, not smooth.

   2%
2. B

   Unsupported: Planck's experiments9% picked this

   Classical wave theory, an incorrect formulation of the nature of radiation, was corrected by Planck and other physicists after Planck performed experiments that

   Planck had an insight, a hypothesis. He never actually performed any experiments that demonstrated radiation exists as particles. He just proposed a new assumption about radiation: "what if it's made up of discrete energies that jump from one unit to another?"

   9%
3. C

   Wrong Emphasis5% picked this

   Planck’s new model of radiation, though numerically consistent with observed data, was slow to win the support of the scientific community, which

   The main clause of this answer is that "Planck's new model was slow to win support". That was not the main point. The main point was more like, "Planck had a new model that thought of radiation as operating in discrete units, rather than in a smooth continuum."

   5%
4. D

   Correct75% picked this

   Prompted by new experimental findings, Planck discarded an assumption of classical wave theory and proposed a picture of radiation that matched experimental results and

   Why this is right

   The main clause here is, "Planck discarded an (Old) assumption and proposed a (New) picture of radiation". The old assumption was "smooth and continuous". The new assumption was "discrete and discontinuous". The other details check out: Planck's work was prompted by experimental findings that showed that blackbodies do not emit more short wavelengths than long wavelengths. And his work was further supported by theoretical justification: the first sentence of the final paragraph says that Einstein and others provided theoretical justification.

   Skill tested: Main Point · how this choice captures the passage's function is the move to repeat next time.

   75%
5. E

   Wrong Catalyst9% picked this

   At the turn of the century, Planck and Einstein revolutionized studies in radiation by modifying classical wave theory in response to experimental results that

   Planck didn't modify classical wave theory; he kind of blew it up. It generated "a new vision in physics". It led to Einstein's discovery that radiation is composed of particles. And it wasn't in response to results suggesting that "the energy of radiation is less at short wavelengths than at long ones". It was in response to experiments showing that blackbody objects weren't emitting energy at the amounts predicted for short vs. long wavelengths. The fact that experimental observations didn't match wave theory's predictions alerted physicists to the possibility that something was wrong with wave theory.

   9%