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In a semiconductor, the electron concentration and hole concentration are in the ratio 7:5. If the ratio of the electron current to the hole current is 7:4, what is the ratio of the drift speed of electrons to that of holes?
- 5/8
- 4/5
- 5/4
- 4/7
Correct answer: 5/4
Solution
Current ratio Ie/Ih = (ne/nh)*(ve/vh). So ve/vh = (7/4)/(7/5) = 5/4.
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