chapter 4

Question 1

define electromagnetic induction

Answer 1

when conductor moves through a magnetic field an emf is induced in that conductor. if the conductor forms a closed circuit , an electrical current will low.this is in acccordance to faradays laws of electromagnetic induction

Question 2

faradays first law of electromagnetic induction

Answer 2

an emf is induced in a circuit whenever there is a charge in the magnetic flux linking with the circuit.

Question 3

faradays second law of electromagnetic induction

Answer 3

the magnitutde of the induced emf is proportional to the rate of flux linkinng to the circuit.

Question 4

direction of emf induced (flemings right hand rule)

Answer 4

motion is thumb pionting up , emf is middle finger pointing side ways flux index finger points in the direction of the magnetic flux

Question 5

name one single phase altenator

Answer 5

generator

Question 6

three phase alternating current

Answer 6

electricity forr domestic uses such as swimming pool motors and lighting , single phase alternating current.large consumers of electtricity make use of three phase ac power.

Question 7

two aadvantagees of threee phase ac power

Answer 7

three phase power is cheaper to generate and to transmit.

three phase motors are more efficient and cannbe constructed in large sizes.

Question 8

simplist aproach to study 3 phase circuits

Answer 8

combination of three single phase circuits