Sketch the diagram in Figure, and label the north and south poles of the electromagnet. Show on your sketch the direction of the magnetic field (as shown by the needle of a plotting compass) at each of the positions A, B, C and D.

A current-carrying solenoid.

State which of the pairs of electromagnets shown in Figure attract one another, and which one repel.

State which of the pairs of electromagnets shown in Figure attract one another, and which one repel.

Figure shows three examples of current-carrying conductors in magnetic fields. For each example, decide whether there will be a magnetic force on the conductor. If there is a force, in what direction will it act? Note the cross in the circle shows the current is into the plane of the paper, as in Figure.

The magnetic field pattern around a current carrying wire. The diagram also shows the convention used to indicate the direction of current.

Figure shows three examples of current carrying conductors in magnetic fields. For each example, decide whether there will be a magnetic force on the conductor. If there is a force, in what direction will it act? Note the cross in the circle shows the current is into the plane of the paper, as in Figure.

The magnetic field pattern around a current carrying wire. The diagram also shows the convention used to indicate the direction of current.

Figure, shows three examples of current carrying conductors in magnetic fields. For each example, decide whether there will be a magnetic force on the conductor. If there is a force, in what direction will it act? Note the cross in the circle shows the current is into the plane of the paper, as in Figure.

The magnetic field pattern around a current carrying wire. The diagram also shows the convention used to indicate the direction of current.

A wire of length$50 cm$  carrying a current lies at right angles to a magnetic field of flux density$5.0mT.$

(a) If${10}^{18}$electrons pass a point in the wire each second, what current is flowing? (electron chargee $=1.60\times 10-19 C.$)