1) A magnetic field is represented by magnetic field lines originating from moving electric charges. 2) The magnetic force on a current-carrying conductor is directly proportional to the current, length of the conductor, and strength of the magnetic field. 3) Examples are provided to demonstrate calculations of magnetic field strength and magnetic force using the equation F = BIL, where F is magnetic force, B is magnetic field strength, I is current, and L is length of the conductor.

1. SUBTITLE

2. If you bring one magnet to the other, it will experience a
magnetic force as it enters the magnetic field of the other magnet.
A magnetic field is represented by magnetic field lines of flux
coming from moving or spinning electricity charged particles
The number of the magnetic field lines in the region of the
magnet is called the magnetic flux. The direction of the magnetic
field is similar to the direction of the magnetic force. The
magnitude of the magnetic field depends on the effect of the
moving charges . The SI unit for magnetic flux density is the tesla (
unit names after the Serbian-American electrical engineer Nikola
Tesla).

3. Magnitude on a Current-Carrying Conductor
The French physicist Andre Marie Ampere determined the
shape of the magnetic field about a conductor carrying a current. He
suggested that there should be a magnetic force on a current-carrying
wire placed in a magnetic field.
The magnetic force is directly proportional to the current (I),
the length of the wire (L) and the magnetic field (B). The magnitude
of the magnetic force sometimes is strong and sometimes is not.
This is due to the angle formation between the wire and the
magnetic field. If the current (I) is perpendicular to the magnetic
field lines, it is in the strongest position. If the wire is parallel to the
magnetic field lines, the magnetic force is weak or zero.

4. In symbols,
F = B I L
where,
B = the magnitude of the magnetic field
I = current of the wire
L = the length of the wire in the magnetic field
F = the magnitude of the magnetic force

5. Example 1. A 90 cm wire is carrying a current of 4.5 A. Find the
magnitude of the magnetic field if the magnitude of the magnetic force is
3.7 x 10-10 N.
Given: Solution:
L = 90cm = 0.90m
I = 4.5 A
F = 3.7 x 10-10 N
Find: B
Using the basic equation for the
magnetic force,
F = B I L
therefore,
B =
𝐹
𝐼𝐿
=
(3.7 𝑥 10_10 𝑁)
(4.5 𝐴)(0.90 𝑚)
=
B =
3.7 𝑥 10_10 𝑁
4.05 𝐴𝑚

6. = 0.91358 x 10 -10 N/Am = a x 10 n
= (9.91358 x 10-1 ) (x 10 -10 )
= 09.14 x 10 -11 N/Am
(add -1 t0 -10 of the exponent since you move 1 time the decimal
point to the right)
N/Am = 1T
B = 9.14 x 10 -11 T

7. Interpretation:
The magnitude of the magnetic field is directly proportional
to the magnetic force. Since the length of the magnetic wire is also
directly proportional to the magnetic force, to the magnetic force,
likewise, a decrease of the length of the wire is also a decrease of
the magnitude of the magnetic field.

8. Example 2. A 2m wire is carrying a current of 9 A. Find the magnitude
of the magnetic field if the magnitude of the magnetic force is 8. 25 x
10-10 N.
Solution
Given:
I = 9A
L = 2m
F = 8. 25 x 10-10 N
Find: B
B =
𝐹
𝐼𝐿
=
8. 25 x 10−10 N
(9𝐴)(2𝑚)
B =
8.25 𝑥 10 −10 𝑁
18𝐴𝑚
B = 0.4583 x 10-10 N/Am
B = (04.583 x 10-1) x (10_10) N/Am
B = 4.58 x 10-11 N/Am
B = 4.58 x 10-11 T
The magnitude of the magnetic field is
4.58 x 10-11 T.

9. Example 3. The magnitude of the magnetic field in a 75 cm wire is
8.16 x 10 -11 T when it carries a current of 6.1 A. Find the magnitude
of the magnetic force.
Solution
Given:
L = 75 cm = 0.75 m
I = 6.1 A
B = 8. 16 x 10 -11 T
Find: F
F = BIL
F = 8. 16 x 10 -11 T (6.1 A)(0.75 m)
F = 8. 16 x 10 -11 𝑁
𝐴𝑚
(6.1 A)(0.75 m)
F = 8. 16 x 10 -11 𝑁
𝐴𝑚
(4.575 Am)
F = 37.332 x 10 -11 N
F = (3.7332 x 10 1) ( x 10 -11) N
F = 3.73 x 10 -10 N
The magnitude of the magnetic force is
F = 3.73 x 10 -10 N.

10. Example 4. The magnitude of the magnetic force in an 80 cm wire is
4. 16 x 10 – 10 N. If the magnitude of the magnetic field is 9.5 x 10 -11 T,
how much is the current carried by the wire?
Solution
F = 4. 16 x 10 – 10 N
B = 9.5 x 10 -11 T
L = 80 cm = 0.8 m
I =
𝐹
𝐵𝐿
=
4. 16 x 10 – 10 N
(9.5 x 10 −11 T)(0.8 𝑚)
I =
4. 16 x 10 – 10 N
9.5 𝑥 10 −11𝑁/𝐴𝑚 (0.8𝑚)
𝑁
𝐴𝑚
. m =
𝑁
𝐴
I =
4. 16 x 10 – 10 N
9.5 x 10 −11 𝑁
𝐴 0.8
=7.6
I = 0.5473 x 101 A
I = 05.473 x 10-1) ( x 101 )A
I =5. 47 A