David Sang and Graham Jones Solutions for Chapter: Electromagnetic Induction, Exercise 4: Questions

Use the idea of magnetic flux linkage to explain why, when a magnet is moved into a coil, the e.m.f. induced depends on the strength of the magnet and the speed at which it is moved.

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 $e.m.f.$

At the surface of the north pole of a bar magnet, the magnetic field is uniform with flux density $0.15T$ The pole has dimensions$1.0 cm\times 1.5 cm$ Calculate the magnetic flux at this pole.

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.

A rectangular coil with $120$ turns is placed at right angles to a magnetic field of flux density $1.2T$. The coil has dimensions$5.0 cm\times 7.5 cm$. Calculate the magnetic flux linkage for this coil.