Electromagnetic effects Flashcards
How can the turning effect of a current carrying coil be amplified
- Increase number of turns on the coil
- Increase the current
- Increase the strength of the magnetic field
What happens when a conductor moves across a magnetic field
It can induce an e.m.f in the conductor
What is a direct current
Produced when a steady current is produced by a battery that moves from negative to positive
What is electromagnetic induction
Process that power stations use to generate electricity
What is a alternating current
The electrons in a alternating current in a circuit moves foward and backward
How does the rotating coil generator work
- The coil is rotated between strong magnets at a fixed rate
- This produces a continuous e.m.f
- current produced is passed to the slip rings
- Output is a.c current
What are the construction of a basic transformer
Made by a soft iton core which is used for voltage transformations
What is a step up transformer
Increases voltage
secondary coil more turns
What is a step down transformer
Decreases voltage
Secondary coil less turns
Transformer equation
(Vp /Vs) = (Np /Ns) (for 100% efficiency)
IpVp = IsVs
(for 100% efficiency)
why power losses in cables are lower
when the voltage is high
When voltages are high, current is low
fixed power = Voltage x current
