IB PHYSICS > 12 Electromagnetic Induction
1 Measure
2 Mech
3 Therm
4 Waves
5 Electric
6 Fields 7 Atomic
8 EPCC
9 Motion in Fields
10 Therm AHL
11 Wave Phen
12 EMI
13 QNP
14 Digital
OPT
PRAC
REVISE

ALTERNATING CURRENT

Describe the emf induced in a coil rotating within a uniform magnetic field.
AC_emf_in_coil.jpg
Students should understand, without any derivation, that the induced emf is sinusoidal if the rotation is at constant speed.

Explain the operation of a basic alternating current (ac) generator.

AC_generator_with_slip_rings.jpg
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.

AC generator applets demonstrate effect of changing frequency.
FENDT AC GENERATOR
FSU AC GENERATOR

Discuss what is meant by the root mean squared (rms) value of an alternating current or voltage.
AC_rms.gif
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.

State the relation between peak and rms values for sinusoidal currents and voltages
transformer_I_rms.png
transformer_V_rms.png
Solve problems using peak and rms values.

Solve ac circuit problems for ohmic resistors.
AC_Resistance_eqn.png
AC_Pmax.png
AC_Pav.png
Describe the operation of an ideal transformer
AC_transformer.gif
AC_transformer_ratios.png
Solve problems on the operation of ideal transformers.
AC generator applets:
FENDT AC GENERATOR
FSU AC GENERATOR