Give three practical applications of the mechanical force exerted on a current-carrying conductor in a magnetic field ...

So the three of them are the following:

1. Generator, it converts the mechanical and chemical energy to an electrical current by using a dynamo inside the generator

2. Motor, best example to it is the motor that runs in a car, it converts the chemical energy in to a mechanical energy by using fuel

3. Transformer, it use coils and magnetic field to regulate current according to its specified voltage.