JEE Main202227 Jul 2022Evening ShiftPhysicsCurrent ElectricityActual
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 in
Options
- AA and B only
- BA and D only
- CB and E only
- DB and C only
Correct answer
B. A and D only
Step-by-step solution
Drift velocity = e τ m E v d = e τ m Δ V l Δ V = Potential difference applied across the wire As temperature increases, relaxation time decreases, hence V d decreases. As per formula, V d ∝ 1 l v d = I   neA   , as it is not mentioned that current is at steady state neither it is mentioned that n is constant for given conductor. So it can't be said that v d is inversely proportional to A . I = n e A v d = V R = V ρ l A v d = e E τ m τ decrease with temperature