Which of the following lamps does NOT suffer from stroboscopic effect?

Concept:

The stroboscopic effect in fluorescent lamp is a phenomenon which causes running or moving equipment to appear stationary or appear to be operating slower than they actually are.

Fluorescent lamps are provided with 50 Hz ac current supply. When operating under this frequency the lamp becomes zero (crosses zero wave) double the supply frequency, i.e, 100 times for 50 Hz frequency per second. Due to the persistence of vision our eyes do not notice those flickering.

However if the light falls on the moving parts due to illusion, they may appear to be either running slow, or in reverse direction or even may appear stationary. This effect is called stroboscopic effect.

This can be prevented by connecting the twin-tube lights in parallel.

Each tube uses a separate choke and a separate starter, and a capacitor is added in series with the second choke, so as to improve the capacitor. We can also avoid the flickering of tube lights.

Explanation:

Incandescent and halogen lights don't have Stroboscopic effect or they have minimal flicker because they are thermal radiators and have a relatively long persistence (due to the thermal capacity of the tungsten filament).