This is a very useful application of the force on a current in a
magnetic field. A steady magnetic field is placed across a tube carrying a conducting liquid, as
shown in Figure 1.
A current is passed through the liquid at right angles to the magnetic field,
and therefore a force is exerted on the liquid which pushes it down the pipe.
This type
of pump is particularly useful since there are no moving parts. It has found application in two
widely different fields: for pumping liquid sodium coolant round a nuclear reactor, and for
pumping blood round the body if the heart is damaged.