Calculate the current in the coil

In summary, a circular coil with 394 turns and an area of 0.78 m2 is placed in a uniform magnetic field of 0.8 T, resulting in a maximum torque of 0.0059 N · m. To calculate the current in the coil, the equation i = torque/(number of turns *A*B) is used. In the second part of the question, the area of the larger coil is calculated using the known area and number of turns, and the length of each loop is found using the circumference formula. The total length of the wire is then used to find the circumference of the larger coil, which is then used to calculate the current using the same equation.
  • #1
mba444
54
0

Homework Statement



A circular coil of 394 turns and area 0.78 m2
is in a uniform magnetic field of 0.8 T. The
maximum torque exerted on the coil by the
field is 0.0059 N · m.
Calculate the current in the coil. Answer in
units of A

Homework Equations


torque= i*A*B



The Attempt at a Solution



what i did is that i solved for the current using the above equation i= torque/(A*B) but i keep getting the wrong answer .. i think because of the number of turns but i don't know were to include it

i need ur help thanks in advance
 
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  • #2
Torque = μ X B, where μ = nIA.
 
  • #3
so is it
i = torque /(number of turns *A*B)
 
  • #4
mba444 said:
so is it
i = torque /(number of turns *A*B)
Yes.
 
  • #5
Assume the 394 turns of wire are used to form
a single-turn coil with the same shape but
much larger area.
What is the current if the maximum torque
exerted on the coil by the field is 0.0059 N · m?


this a second part of the question but i really didnt understand the difference
 
  • #6
You need to figure out the area of this larger coil. Hint: What's the length of the wire?
 
  • #7
i tried to figure out the length where i came up with this equation but still i couldn't figure what to put for the F

length = F/(i*B)

im kind of lost
 
  • #8
Figuring out the length of the wire is a geometry problem. You had a coil of a given area and number of turns. What was the circumference of that coil?
 
  • #9
C= 2*pi*r
 
  • #10
mba444 said:
C= 2*pi*r
Good. Use the known area to find the radius.
 
  • #11
ok i did so know
1 loop = 2*pi*r (i just found)
394= X
so do i do the cross multiplication to solve for X which is the new area
 
  • #12
mba444 said:
ok i did so know
1 loop = 2*pi*r (i just found)
394= X
so do i do the cross multiplication to solve for X which is the new area
Do this:
Use the area of the original coil to solve for the radius, using A = pi*r².
Use the radius to find the length of each loop, using the circumference formula.
Find the total length of the wire by multiplying the length of each loop by the number of loops.
That becomes your new circumference of your big coil. Work backwards to find, its radius then area.
 
  • #13
ok thanks a lot i got it know .. sorry if i wasted your time
 
  • #14
i got for the larger area = 121084 m^2

i plugged in this eqs i = (.0059)/(394*121084*0.8)

but i got the wrong answer =(
 
  • #15
mba444 said:
i got for the larger area = 121084 m^2
That looks OK.

i plugged in this eqs i = (.0059)/(394*121084*0.8)
When used to make the giant coil there's only one turn.
 
  • #16
thanx again i got the right answer
 

1. How do I calculate the current in a coil?

The formula for calculating current in a coil is I = V/R, where I is the current in amps, V is the voltage across the coil in volts, and R is the resistance of the coil in ohms.

2. What factors affect the current in a coil?

The current in a coil is affected by the voltage across the coil, the resistance of the coil, and the inductance of the coil, which is a measure of how the coil responds to changes in current.

3. How do I measure the voltage across a coil?

To measure the voltage across a coil, you can use a voltmeter, which is a device that measures the potential difference between two points in an electrical circuit.

4. What is the purpose of calculating the current in a coil?

Calculating the current in a coil is important for understanding how much electricity is flowing through the coil. This information can be used to design and optimize electrical systems, such as motors and transformers, that use coils.

5. Can I use the same formula to calculate the current in any coil?

The formula I = V/R can be used to calculate the current in any coil, as long as the voltage and resistance values are known. However, for more complex coils with non-linear relationships between voltage and current, a more advanced formula may be needed.

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