The ratio of the concentration of electrons to that of holes in a semiconductor is 7 5 and the ratio of currents is 7 4 . Then, the ratio of their drift velocities is

As I = n e A v d ⇒ I e I h = e n e A v e e n h A v h = n e v e n h v h ⇒ v e v h = I e I h × n h n e = 7 4 × 5 7 = 5 4

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PhysicsCurrent ElectricityMicroscopicEasy2 minPYQ_2020

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The ratio of the concentration of electrons to that of holes in a semiconductor is $\frac{7}{5}$ and the ratio of currents is $\frac{7}{4}$ . Then, the ratio of their drift velocities is

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Answer:

Solution:

As
$I = n e A v_{d}$

$\Rightarrow \frac{I_{e}}{I_{h}} = \frac{e n_{e} A v_{e}}{e n_{h} A v_{h}} = \frac{n_{e} v_{e}}{n_{h} v_{h}}$

$\Rightarrow \frac{v_{e}}{v_{h}} = \frac{I_{e}}{I_{h}} \times \frac{n_{h}}{n_{e}} = \frac{7}{4} \times \frac{5}{7} = \frac{5}{4}$

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:Current ElectricitySubtopic:Microscopic

⏱ 2mℹ️ Source: PYQ_2020

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