JAMB - Physics (1999 - No. 29)
At what frequency would a 10H inductor have a reactance of 2000Ω?
π/200Hz
π/100Hz
100/πHz
100πHz
Explication
Inductive reactance XL = 2πfL
∴ 2πfL = 2000Ω
then f = 2000Ω/2 x π x 10
f = 100/πHz
∴ 2πfL = 2000Ω
then f = 2000Ω/2 x π x 10
f = 100/πHz