Chapter 26 Mag Fields & Electromagnetism

Question 1

How do we represent magnetic patterns

Answer 1

Magnetic field lines
North Pole to South Pole
Direction of the force that a free mag North Pole would experience at that point
Strongest where field lines are closest together

Question 2

Fleming’s left-hand rule

Answer 2

Thumb = motion/force
1st finger= field
2nd finger = current

Question 3

Motor effect

Answer 3

External mag field of mags + mag field of current-carry conductor = mag fields combined

Question 4

Magnetic flux density

Answer 4

Point in space is the force experienced per unit length by a long straight conductor carrying unit current and placed at right angles to the field at that point
In tesla

Question 5

Magnetic flux density derived

Answer 5

B = F/IL I= current of conductor, L= length of the conductor in the uniform mag field
Force on conductor: F= BIL

Question 6

Magnetic flux formula + definition

Answer 6

Number of mag field lines passing normally to a given area

Fie = BA

Question 7

Currents crossing fields at 90° and at other angles

Answer 7

At 90°: max force but parallel to field, zero force

At other angles: F=BILsin(theta)

Question 8

Forced between currents

Answer 8

Anti-parallel currents: 
One flowing into and one flowing out
Extra-strong field in between 
Wires pushed together = Repulsion 
Parallel currents: 
Mag fields cancel out in between 
Wires pushed together = Attraction, two forces are equal but opposite in direction