# Force in magnetic field

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#1
Would it work if I used the question F = BILsinx with L being the perimeter of the coil? (so 1.20m)
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11 months ago
#2
(Original post by Mlopez14)
Would it work if I used the question F = BILsinx with L being the perimeter of the coil? (so 1.20m)
The equation F= BIL sinθ will work if you apply it correctly. Note that the θ that appears in the equation is different from the θ that appears in the question.

The following video may help

L is the NOT the perimeter as the different current segment of the coil makes different orientation with respect to the magnetic field.
Hint: We only need to consider the 0.40 m segment.

Are you doing A level or University Physics?
0
#3
A level,
I am aware that L is length, but I wasn't sure which length to take
Last edited by Mlopez14; 11 months ago
0
11 months ago
#4
(Original post by Mlopez14)
A level,
I am aware that L is length, but I wasn't sure which length to take
It would be great that you explain what you “understand” of the equation F= BIL sinθ.

Different “current” segment of the coil makes with different angles with the magnetic field lines.

How is “0.40 m-current” segment orientated with respect to the magnetic field? Same question for “0.20 m-current” segment.
0
11 months ago
#5
(Original post by Mlopez14)
A level,
I am aware that L is length, but I wasn't sure which length to take
The following websites may help you to decide which length of the coil to take.
http://hyperphysics.phy-astr.gsu.edu...c/forwir2.html
https://courses.lumenlearning.com/ph...ing-conductor/
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#6
(Original post by Eimmanuel)
It would be great that you explain what you “understand” of the equation F= BIL sinθ.

Different “current” segment of the coil makes with different angles with the magnetic field lines.

How is “0.40 m-current” segment orientated with respect to the magnetic field? Same question for “0.20 m-current” segment.
B = the magnetic flux. I = current L = length of wire sin0 is the angle that wires make with the magnetic field lines. That's how I understand it
0
11 months ago
#7
(Original post by Mlopez14)
B = the magnetic flux. I = current L = length of wire sin0 is the angle that wires make with the magnetic field lines. That's how I understand it

Some modification to your understanding is required IMO.

The symbol B denotes magnetic flux density or magnetic field strength or magnetic field vector. In studying electromagnetic induction, you would encounter magnetic flux which is a scalar quantity but magnetic flux density is a vector quantity.

The symbol θ is known as theta it is the angle between the direction of current and magnetic field (lines) NOT sin θ.

I think I should change the equation to

F= BIL sin ϕ

to avoid confusion of the usage of θ in the question.

ϕ represents the angle between the direction of current and magnetic field (lines).

What is the angle ϕ between the “0.40 m-current” and the magnetic field from the top view?
Spoiler:
Show

magnetic field is perpendicular the “0.40 m-current”segment.

What is the angle ϕ between the “0.20 m-current” and the magnetic field from the top view?

Once you have figured out the answers to the 2 questions, the rest of the questions should be easy.
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