When an aircraft flies from east to west, its wings are an electrical conductor cutting across the Earth's magnetic flux. In the northern hemisphere, state which wingtip (left or right) will become positive. State and explain what will happen to this wingtip in the southern hemisphere.

In an experiment to investigate the factors that affect the magnitude of an induced e.m.f., a student moves a wire back and forth between two magnets, as shown in Figure ,State why the e.m. f. generated in this way is almost zero.

A wire is moved horizontally in a horizontal magnetic field.

In the type of generator found in a power station, a large electromagnet is made to rotate inside a fixed coil. An e.m.f. of 25 kV is induced; this is an alternating voltage of frequency $50Hz.$

(a) State the factor that determines the frequency.

In the type of generator found in a power station, a large electromagnet is made to rotate inside a fixed coil. An $e.m.f.$of$25kV$ is induced; this is an alternating voltage of frequency $50Hz.$

(b) Suggest the factors that you think would affect the magnitude of the induced $e.m.f.$

A solenoid has diameter $5.0 cm$ length $25 cm$and $200$ turns of wire. A current of $2.0A$ creates a uniform magnetic field of flux density $2.0\times {10}^{-5}$$T$ through the core of this solenoid.

A solenoid.

(a) Calculate the magnetic flux linkage for this solenoid. 

A solenoid has diameter $5.0 cm$ length $25 cm$and $200$ turns of wire. A current of $2.0A$ creates a uniform magnetic field of flux density $2.0\times {10}^{-5}$$T$ through the core of this solenoid.

A solenoid.

(b) The diameter of the solenoid is $5.0\pm 0.2 cm.$ Determine the absolute uncertainty in value of magnetic flux linkage for this solenoid. You may assume all the other quantities have negligible uncertainties.