why does the fuse not blow?

The fuse is a short... all fuses are short circuits just by being a fuse ...unless they blow... when they become open circuit. "Short" means having no load.

The lamp is a load - it has resistance and the resistance limits the amount of current that flows. As long as the resistance limits the current to an amount below the capacity of the fuse - the fuse will not blow (melt).

If for any reason too much current flows the fuse will blow.

Fuses are used to limit current flow in the event of a fault happening - otherwise the wiring can get very hot very quickly and start a fire.

We have fuses to stop the house burning down.

When you switch a light on the live is connected to the load - the light bulb. No current can flow unless there is a neutral return path.

A short circuit is a circuit with No Load - infinite current can flow - bad things can happen.

Peccavi
February 2011

when you pass a current through a wire,it heats up,
if you put the wire in a vacuum,add gas,then you have a bulb,

mm
February 2011

because of the resistance of the filament in the bulb

mm
February 2011