Elecrodynamics

Question 1

Induced emf

Answer 1

The total amount of electrical energy supplied per unit positive charge

Question 2

Magnetic fields

Answer 2

Produced by magnets or by moving electrical charges. magnetic field lines are drawn to represent the direction of the magnetic field at point. The symbol for magnetic field is B and it’s unit is the Tesla (T)

Question 3

Magnetic flux density

Answer 3

Is a representation of the magnitude and direction of the magnetic field

Question 4

Magnetic flux linkage

Answer 4

The product of the number of turns on a coil and the flux through a coil

Question 5

Magnetic flux

Answer 5

For a loop of area (A) in the presence of a uniform magnetic flux density (B), the magnetic flux (Ø) passing through the loop is defined as Ø=BAcos0 where 0 is the angle between the Magen flux density (B) and the normal to the loop of area (A)

Question 6

Lenz’s Law

Answer 6

The induced current flows in a direction so as to set up a magnetic field to oppose the change in magnetic flux

Question 7

Diode

Answer 7

A component that only allows current to flow in one direction

Question 8

Motor

Answer 8

A device which coverts electrical energy into mechanical energy

Question 9

Generator

Answer 9

A device which converts mechanical energy into electrical energy

Question 10

DC

Answer 10

Direct current. Current flowing in one direction only

Question 11

Conventional current

Answer 11

The rate of flow of positive charge from the positive terminal of the cell to the negative terminal

Question 12

Commutator

Answer 12

A device which ensures that the direction of the current in a coil is reversed every half revolution

Question 13

AC

Answer 13

Alternating current. Current which reverses direction periodically

Question 14

Faradays Law

Answer 14

The emf induced is directly proportional to the rate of change of magnetic flux (flux linkage)