WAEC Physics 2018 Objective — Question 47
Question 47 of 50 from the West African Examinations Council (WAEC) Physics 2018 Objective paper, with the correct answer and a full explanation.
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In which of the following situations is the photoelectric effect employed? I. Automatic devices for switching on light at dusk II. Automatic doors in departmental stores III. Automatic devices for switching on air conditions IV. Automatic voltage stabilization
- A. I and II onlyCorrect
- B. II and IV only
- C. III and IV only
- D. I and IV only
Explanation
Light-sensitive switching (dusk sensors) and light-beam-triggered automatic doors both rely directly on the photoelectric effect; air-conditioning and voltage stabilisation do not.
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