Neco 2025 Physics Question 23

Practice objective / multiple choice question 23 from the 2025 Neco Physics examination.

Neco 2025 Physics Objective / Multiple Choice Hard Difficulty

Question 23 NECO • 2025 • PHYSICS • objective

In a photoelectric experiment a metal surface of unknown work function \(\phi\) is illuminated with monochromatic light of wavelength \(500\ \text{nm}\), producing a stopping potential of \(0.80\ \text{V}\). When the wavelength is changed to \(400\ \text{nm}\) the stopping potential increases by \(0.62\ \text{V}\). (i) Determine the work function \(\phi\) in electron‑volts. (ii) Find the threshold wavelength \(\lambda_{0}\) (in nanometres) for this metal. (Use \(h c = 1240\ \text{eV·nm}\).)

A. φ = 1.20 eV, λ₀ ≈ 1030 nm

B. φ = 1.68 eV, λ₀ ≈ 800 nm

C. φ = 2.10 eV, λ₀ ≈ 590 nm

Correct Answer D. φ = 1.68 eV, λ₀ ≈ 738 nm

Correct Answer

Correct Option:

φ = 1.68 eV, λ₀ ≈ 738 nm

This is Neco 2025 Physics Question 23. It is one of the objective questions from the 2025 Neco Physics examination.

Difficulty level: Hard .

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