Drift velocity in metal is

This question was previously asked in
ESE Electronics 2014 Paper 1: Official Paper
View all UPSC IES Papers >
  1. inversely proportional to the force on an electron due to applied electric field
  2. directly proportional to the mass of an electron 
  3. proportional to the mobility of an electron
  4. inversely proportional to the strength of the applied electric field

Answer (Detailed Solution Below)

Option 3 : proportional to the mobility of an electron
Free
ST 1: UPSC ESE (IES) Civil - Building Materials
6.2 K Users
20 Questions 40 Marks 24 Mins

Detailed Solution

Download Solution PDF

Concept:

The drift velocity is directly proportional to the electric field, i.e.

Vd ∝ E

Vd = μE

The proportionality constant 'μ' defined as:

\(\mu = \frac{{{v_d}}}{E} = \frac{{q\tau }}{m}\)

Observation

  • Drift velocity is proportional to the mobility of the electron, i.e. more the mobility, the more will be the drift velocity.
  • Drift velocity is directly proportional to the electric field applied.
  • Drift velocity is inversely proportional to the mass of the electron.

 

Notes:

  • Mobility defines how quickly can an electron move in metal or semiconductor under the influence of the electric field.
  • When an electric field is applied, the electrons and holes are accelerated by it.
  • The electron moving with a finite average velocity is called drift velocity.
Latest UPSC IES Updates

Last updated on May 28, 2025

->  UPSC ESE admit card 2025 for the prelims exam has been released. 

-> The UPSC IES Prelims 2025 will be held on 8th June 2025.

-> The selection process includes a Prelims and a Mains Examination, followed by a Personality Test/Interview.

-> Candidates should attempt the UPSC IES mock tests to increase their efficiency. The UPSC IES previous year papers can be downloaded here.

More Carrier Transport Questions

Get Free Access Now
Hot Links: all teen patti teen patti - 3patti cards game downloadable content teen patti gold apk download teen patti casino apk teen patti rules