WAEC Physics 2021 Objective — Question 43
Question 43 of 50 from the West African Examinations Council (WAEC) Physics 2021 Objective paper, with the correct answer and a full explanation.
Advertisement
43. The electrons in a cathode-ray tube are produced by
- A. heating a metal filamentCorrect
- B. ionization of the air
- C. applying a magnetic field to the y-plates
- D. applying an electric field to the x-plates
Explanation
Electrons are produced by thermionic emission — heating a metal filament (the cathode) until electrons are emitted.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.