COMEDK · Physics · 30. Semiconductors
In a given semiconductor, the ratio of the number density of electron to number density of hole is \(2: 1\). If \(\dfrac{1}{7}\)th of the total current is due to the hole and the remaining is due to the electrons, the ratio of the drift velocity of holes to the drift velocity of electrons is :
- A \(\dfrac{3}{2}\)
- B \(\dfrac{1}{3}\)
- C \(\dfrac{2}{3}\)
- D \(\dfrac{3}{1}\)
Answer & Solution
Correct Answer
(B) \(\dfrac{1}{3}\)
Step-by-step Solution
Detailed explanation
Let \(n_e\) and \(n_h\) be the number densities of electrons and holes respectively. Given \(\dfrac{n_e}{n_h} = \dfrac{2}{1}\), so \(n_e = 2n_h\). The total current \(I\) is the sum of electron current \(I_e\) and hole current \(I_h\). Given \(I_h = \dfrac{1}{7}I\), it follows…
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