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 $=1.60\times 10-19 C.$)

A wire of length $50cm$ carrying a current lies at right angles to a magnetic field of flux density$5.0mT.$ What force acts on the wire?

In the examples shown in the diagrams in Figure, which current balances will tilt? Will the side carrying the current tilt upwards or downwards?

Four current balances- will they tip?

In the arrangement shown in Figure, the balance reading changes from 1$102.48 g$ to $104.48 g$ when the current is switched on. Explain why this happens and give the direction and the size of the force on the wire when the current is on. What is the direction of the current in the wire?

Using an electronic balance.