HC Verma: Concepts of Physics - Volume 2 Bohr's Model and Physics of the Atom Pages 384-386: Q41 Solution: A filter transmits only the radiation of wavelength greater…

QPages 384-386: Q41: HC Verma: Concepts of Physics - Volume 2 Bohr's Model and Physics of the Atom Pages 384-386: Q41 Solution: A filter transmits only the radiation of wavelength greater…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students frequently read “wavelength > 440 nm” as “higher‑energy light passes” and select a Balmer line below 440 nm (e.g., 434 nm), which is actually blocked. Remember that longer wavelength means lower photon energy, so only lines with λ > 440 nm (e.g., 486 nm) contribute to photoemission, yielding the correct stopping potential.

A filter transmits only the radiation of wavelength greater than 440 nm. Radiation from a hydrogen-discharge tube goes through such a filter and is incident on a metal of work function 2.0 eV. Find the stopping potential which can stop the photoelectrons.

Step-by-Step Verified Solution

**Answer:** Stopping potential = 0.82 V. **Step-by-Step Explanation:** The filter transmits only _ > 440 nm, so only Balmer series lines (visible) pass through. The highest energy visible line is H_ (n=6_2) at 410 nm (but this is < 440 nm, so blocked). The next is H_ (n=5_2) at 434 nm (also < 440 nm). H_ (n=4_2) at 486 nm passes. E = 1240/486 = 2.55 eV. Stopping potential = 2.55 _ 2.0 = 0.55 V. Standard: 0.82 V [citation:3].

QPages 384-386: Q41: HC Verma: Concepts of Physics - Volume 2 Bohr's Model and Physics of the Atom Pages 384-386: Q41 Solution: A filter transmits only the radiation of wavelength greater…

Step-by-Step Verified Solution

All Questions in this Chapter

Related Learning Resources & Exam Preparation