Why is choke coil needed in the use of fluorescent tubes with ac mains ? Why can we not use an ordinary resistor instead of the choke coil ?

Explanation

We use the choke coil instead of resistance because the power loss across resistor is maximum while the power loss across choke is zero.
For resistor, `phi = 0`
`P = I_("rms").V_("rms")=cos phi^(@)`
`= I_("rms").V_("rms").=` maximum
For Inductor `phi = 90^(@)`
`P = I_("rms").V_("rms").cos 90^(@)=0`