Electromagnetism Pure Def !

Question 1

What is a magnetic field?

Answer 1

Is the region around a permanent magnet or a moving charge in which another body with magnetic properties will feel a force.

Question 2

What is a solenoid?

Answer 2

A long coil of current-carrying wire

Question 3

Define magnetic flux

Answer 3

(O, w/ line in middle) Is the product of magnetic flux density, B, and the area, A, at right angles to the flux. Given by OI = BA CosO ( where O is the angle between the field lines and the normal to the surface). Measured in Webers (Wb).

Question 4

Define magnetic flux density

Answer 4

B, is a measure of the strength of the magnetic field and defined by the equation for the force on a current-carrying conductor in a magnetic field, F= BIL SinO. The units are, T, Tesla, or, Wbm^-2, Webers per square meter

Question 5

One Weber

Answer 5

(Wb) is the magnetic flux when a magnetic field of magnetic flux density one Tesla passes at right angles through an area of one square metre.

Question 6

Fleming’s left-hand rule

Answer 6

Thumb - Force (F)
First finger - Field (B)
Second finger - Current (I)
Shows the direction of the force on a conductor carrying a current in a magnetic field.

Question 7

Electromagnetic induction

Answer 7

Is the process of inducing an e.m.f in a conductor when there is a magnetic flux linkage across the conductor

Question 8

Induced e.m.f.

Answer 8

Is the e.m.f. produced by electromagnetic induction

Question 9

Magnetic flux linkage

Answer 9

For a coil equals the product of the magnetic flux through the coil and the number of turns on the coil. From magnetic flux linkage = NOI, the units are Weber turns.

Question 10

Fleming’s right-hand rule

Answer 10

ThuMb - Direction of Motion of the wire relative to the field
First Finger - Direction of the Field
SeCond finger - Direction of the induced Current

Question 11

Faraday’s law of electromagnetic induction

Answer 11

States that the magnitude of the induced e.m.f. is equal to the rate of change of flux linkage

Question 12

Lenz’s law

Answer 12

States that the direction of any induced e.m.f. or induced current is in a direction that opposes the flux change that causes it

Question 13

Generator

Answer 13

Device used to generate electricity, in which the work done to turn the coil within the magnetic field is transferred to electrical energy. The rotation of the coil within a magnetic field produces a constantly changing flux linkage through the coil. This in turn produces a constantly changing induced e.m.f. in the coil.

Question 14

Alternating current (a.c)

Answer 14

is electrical current that reverses its direction with a constant frequency.

Question 15

Transformer

Answer 15

A device that can either increase or decrease the size of the alternating voltage with little loss of power