JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Current Electricity

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A. The drift velocity of electrons decreases with the increase in the temperature of conductor.
B. The drift velocity is inversely proportional to the area of cross-section of given conductor.
C. The drift velocity does not depend on the applied potential difference to the conductor.
D. The drift velocity of electron is inversely proportional to the length of the conductor.
E. The drift velocity increases with the increase in the temperature of conductor.

Choose the correct answer from the options given below:

(A)A and B only
(B)A and D only✓ Correct
(C)B and E only
(D)B and C only

Answer: (B)

Solution

Drift velocity

v_{d} = \frac{e τ}{m} E = \frac{e τ}{m} \frac{V}{ℓ}

, where

τ

is relaxation time. Statement A is correct: as temperature increases,

τ

decreases, so

v_{d}

decreases. Statement B is incorrect without specifying constant current. Statement C is incorrect:

v_{d}

depends on

V

. Statement D is correct:

v_{d} \propto \frac{1}{ℓ}

. Statement E contradicts A. Thus A and D are correct.

JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Single correct option

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JEE Main · 2022 · 27 Jul 2022 · Shift 2 · Current Electricity

Solution

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