Electromagnetic Induction

 

Topic #	Old Topic	Old # Hrs	New Topic #	New Topic	New # Hrs
11	Electromagnetism	9	12	Electromagnetic induction	6
11.1	Electrostatic potential	3	9.3	Electric field, potential and energy (moved to topic 9.3)
11.2	Electromagnetic induction	4	12.1	Induced electromotive force (emf)	3
11.3	Alternating Current	2	12.2	Alternating current	2
			12.2.3	Describe the effect on the induced emf of changing the generator frequency. Students will be expected to compare the output from generators operating at different frequencies by sketching appropriate graphs.
			12.2.4	Discuss what is meant by the root mean squared (rms) value of an alternating current or voltage. Students should know that the rms value of an alternating current (or voltage) is that value of the direct current (or voltage) that dissipates power in a resistor at the same rate. The rms value is also known as the rating.
			12.2.5	State the relation between peak and rms values for sinusoidal currents and voltages.
			12.2.6	Solve problems using peak and rms values.
			12.3	Transmission of electrical power	1
			12.3.1	Outline the reasons for power losses in transmission lines and real transformers.
			12.3.2	Explain the use of high-voltage step-up and step-down transformers in the transmission of electrical power. Students should be aware that, for economic reasons, there is no ideal value of voltage for electrical transmission.
			12.3.4	Suggest how extra-low-frequency electromagnetic fields, such as those created by electrical appliances and power lines, induce currents within a human body.
			12.3.5	Discuss some of the possible risks involved in living and working near high-voltage power lines. Students should be aware that current experimental evidence suggests that low-frequency fields do not harm genetic material. Students should appreciate that the risks attached to the inducing of current in the body are not fully understood. These risks are likely to be dependent on current (density), frequency and length of exposure. Aim 8 and TOK: The use of risk assessment in making scientific decisions can be discussed here. The issues of correlation and cause, and the limitations of data, are also relevant here.