JEE Main201910 Apr 2019Morning ShiftPhysicsCurrent ElectricityActual
A current of 5 A passes through a copper conductor (resistivity = 1.7 × 10 - 8 Ω m ) of radius of cross-section 5 m m . Find the mobility of the charges if their drift velocity is 1.1 × 10 - 3 ms - 1 .
Options
- A1.5 m 2 V - 1 s - 1
- B1.8 m 2 V - 1 s - 1
- C1.0 m 2 V - 1 s - 1
- D1.3 m 2 V - 1 s - 1
Correct answer
C. 1.0 m 2 V - 1 s - 1
Step-by-step solution
Mobility μ = V d E ⇒ μ = V d E = V d l V = V d l i R = V d A l i ρ l μ = 1.1 × 10 - 3 × π 5 × 10 - 3 2 5 × 1.7 × 10 - 8 = 1.0   m 2   V - 1   s - 1