Electronics Paper 2, Nov/Dec. 2012

Questions:	1	2	3	4	5	6	7	8	9	10	Main

General Comments
Weakness/Remedies
Strength

Question 1

Question 1
(a) State the function of the following in a cathode ray tube:
           (i)        electron gun;
           (ii)       X-plates;
           (Hi)     Y-plates;
           (iv)      fluorescent screen.
(b) State two applications of the cathode ray tube.

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OBSERVATION

TThe expected answers were:
      (a)       (i)        Electron gun - emits high velocity beam of electrons
                 (ij)        X-plates - causes the horizontal deflection of the electron beam
                  (iii)       Y-plates - causes the vertical deflection of the electron beam
                  (iv)      Flourescent screen - emits visible lightwhen struck by the
electron beam
      (b)       - Television                - Picture display
                  - Radar systems        - Signal display
- Computer display - Waveform display (CRO)
The question was on Electron Emission and Thermionic Devices. It was quite
unpopular with the candidates. Quite a few candidates correctly responded to
this question.