This test is run by .
Note that your final mark will not be saved in the system.
Note that your final mark will not be saved in the system.
Electromagnetism GapFill
Target Level
C
Running Total
0
0%
Attempt
1 of 3
You must fill all the gaps before clicking ‘Check Answers!’
Electromagnetism describes how electric currents and magnetic fields interact; currents generate magnetic fields, and magnetic fields can induce currents. One of the key laws of electromagnetism is the Faraday-Lenz law, which states that an induced emf is proportional to the rate of change of magnetic flux linkage, in the direction opposing the inducing change, which can be written more succinctly as
. For a rotating coil, the induced emf follows the equation
.
Electricity is transmitted as an alternating current, with current and potential difference being sinusoidal; this means that the power dissipated by a wire carrying an alternating current can be written as . Alternating currents can be seen by using .
A transformer is a device which uses two coils to induce an emf to raise or lower a potential difference as necessary. A step-up transformer will in the secondary coil compared to the transformer's primary coil. The equation can be used to find the potential differences across the coils and the number of turns in the coils.
Transformers will never be perfectly efficient. Inefficiencies might be caused by , which cause heating in the coils of the transformer. The efficiency of a transformer equals . The power lost over a component or wire is expressed in terms of the power transmitted as .
Electricity is transmitted as an alternating current, with current and potential difference being sinusoidal; this means that the power dissipated by a wire carrying an alternating current can be written as . Alternating currents can be seen by using .
A transformer is a device which uses two coils to induce an emf to raise or lower a potential difference as necessary. A step-up transformer will in the secondary coil compared to the transformer's primary coil. The equation can be used to find the potential differences across the coils and the number of turns in the coils.
Transformers will never be perfectly efficient. Inefficiencies might be caused by , which cause heating in the coils of the transformer. The efficiency of a transformer equals . The power lost over a component or wire is expressed in terms of the power transmitted as .