JEE Main · 2019 · Shift-ImediumATOM-092

Which of the graphs shown below does not represent the relationship between incident light and the electron ejected…

Structure of Atom · Class 11 · JEE Main Previous Year Question

Question

Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface?

Options
  1. a

    image

  2. b

    image

  3. c

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  4. d

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Correct Answera

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Detailed Solution

🧠 The Einstein Binary Einstein's photoelectric theory separates "Number" from "Energy." Intensity controls how many photons (and thus electrons) flow, while Frequency controls how much punch (Kinetic Energy) each electron has.

🗺️ The Graph Audit

  1. KE vs Frequency: This is a linear graph with a positive intercept on the x-axis (threshold frequency). Correct.
  2. Number of Electrons vs Intensity: This is a direct proportion passing through the origin. Correct.
  3. KE vs Intensity: Kinetic energy is independent of intensity. The graph should be a flat, horizontal line.
  4. Incorrect Representation: Option (a) incorrectly shows Kinetic Energy increasing with Intensity. In reality, shine a brighter light only gives you more electrons, not faster ones.

The "One Photon, One Electron" Rule Think of photons as individual packets. Making the light brighter just adds more packets; it doesn't change the size of each packet.

⚠️ Common Traps Many students intuitively feel that "more light = more energy." While true for the total beam, it is false for the individual electron.

Answer: (a)\boxed{\text{Answer: (a)}}

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Which of the graphs shown below does not represent the relationship between incident light and the… (JEE Main 2019) | Canvas Classes