Out of the following devices which devices use electromagnets?
Electric bell
Electric heater
An electromagnet is what we obtain when we connect a solenoid to a circuit. When current passes through the solenoid, the magnetic field lines around the solenoid are similar to that of a bar magnet. An electromagnet is preferred over permanent magnets due to the fact that its strength can be varied, its poles can be reversed and it can be switched on or off, making it into a magnet when we require.
Out of the given options, an electric fuse doesn't need an electromagnet. It is used to make or break a circuit. A bulb doesn't need an electromagnet either.
An electric bell uses an electromagnet to periodically attract the striker to the gong. An electric generator has a coil in it that rotates inside a magnetic field to generate electricity. It uses an electromagnet too, as its strength can be increased to generate more current.