CBSE Class 12-science Answered
The choke is nothing but a coil wound over a core; in other words, an inductor. When you switch on the tube light, the sudden surge of current induces a back-EMF across the choke. This voltage is applied across the electrodes of the tube light and it strikes an arc.
Once the arc is struck, the current flows through the gas inside the tube. There is no further point in letting it flow through the choke after the tube glows steadily, as this would only result in losses. Therefore, the choke needs to be cut-off after the tube light glows steadily. This is done by the starter, which cuts off the current through the choke after some time. (It allows the current to flow through the choke only during the starting, and hence it is called a starter).