JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Current Electricity

The drift velocity of electrons for a conductor connected in an electrical circuit is

V_{d}

. The conductor in now replaced by another conductor with same material and same length but double the area of cross section. The applied voltage remains same. The new drift velocity of electrons will be

(A) $V_{d}$ ✓ Correct
(B) $\frac{V _{d}}{2}$
(C) $\frac{V _{d}}{4}$
(D) $2 V_{d}$

Answer: (A)

Solution

The drift speed is

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

, which depends on the applied voltage, the length, the material through the relaxation time

τ

, and the electron's charge and mass, but not on the cross-sectional area. Since the voltage, length and material are unchanged, doubling the area leaves every one of these factors the same, so the drift velocity remains

V_{d}

JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Single correct option

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JEE Main · 2023 · 31 Jan 2023 · Shift 1 · Current Electricity

Solution

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