waecE-LEARNING
Physics Paper 2, Nov/Dec. 2011  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Main
General Comments
Weakness/Remedies
Strength
















Question 9

 Explain briefly the principle of action of a discharge tube.

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comments

 This question was poorly attempted by the few candidates that attempted it.  Many of them described the discharge tube instead of explaining its working principle.

The expected answer is:

 The pressure of air/gas in the closed tube is reduced using a (vacuum) pump.  A (very)high voltage is applied across the electrodes.  The remaining air/gas at (very)  low pressure conducts giving rise to a discharge  (between the electrodes).

 


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