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Radiation emitted in the hydrogen atom transition from n = 3 to n = 2 is incident on a metal surface and ejects photoelectrons. These electrons then enter a magnetic field of magnitude 3 × 10⁻⁴ T. If the maximum radius of the circular trajectory traced by the electrons is 10.0 mm, the metal’s work function is nearest to:

1. 1.8 eV
2. 1.1 eV
3. 0.8 eV
4. 1.6 eV

Correct answer: 1.1 eV

Solution

The correct option is right because the energy of the emitted photons from the hydrogen transition is calculated to be approximately 1.89 eV, and after accounting for the work function and the kinetic energy of the ejected photoelectrons, the work function is determined to be closest to 1.1 eV.

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