Question

In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be ______.

Options

• 10

• 20

• 30

• 40

Answer 1

In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be 10.

Explanation:

Given dI = 0.25 - 0 = 0.25A

dt = 0.025 ms

Induced voltage

E_ind = 100v

Self-inductance, L =?

Using, E_ind = `(Deltaphi)/(Delta"t")`

⇒ 100 = `("L"(0.25-0))/(0.25xx10^-3)`

⇒ L = 0.01

H = 10 mH