# Maximum and Minimum flux in a coil [closed]

A coil of 100 turns and a diameter of 3.18cm is mounted on an axle through a diameter and is place in a uniform magnetic field, where the flux density is 0.01T, in such a manner that the axle is normal to the field direction. Calculate. (i) The maximum flux through the coil and the position at which it occurs. The maximum flux through the coil and the position at which it occurs.

(ii)The minimum flux through the coil and the position at which it occurs.

(iii) The flux through the coil when it's plane is inclined at 60 degrees to the flux direction.

Data N= 100t d= 3.18cm = 0.0318cm B= 0.01T Angle(teta) =60 degrees

SLN. (iii) Flux =BAsin get a But A= pi*r square But r=1/2*d = d/2

A=pi(d/2)square =3.142*0.00101142/4 =0.0031773161/4 =0.00079m or 79mm It implies that Flux = BA sin-teta = 0.01*0.00079*0.866 = 0.0000079*0.866 = 0.0000068416wb or 0.00684mwb

Now my problem is the formular for finding (i) and (ii) pls any help

## closed as off-topic by Dan Mills, Olin Lathrop, winny, Voltage Spike, Kevin ReidMay 23 '18 at 19:39

• This question does not appear to be about electronics design within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

• Smells of homework - what have you done so far? – Solar Mike May 19 '18 at 12:13
• I'm voting to close this question as off-topic because it is homework with no attempt at a solution. Show us what you have done so far and we will help, but "Do my homework for me" is not a good look around here. – Dan Mills May 19 '18 at 12:15
• I've been able to come out with the area A as A= pi r square – user189315 May 19 '18 at 12:17
• And r = 1/2 × d = d/2. So r=d/2. Which gives A=pi (d/2) square. Substituting in values, A= 3.142*0.00101142/4. Which gives A=0.00079m. But my problem is the formula for finding the maximum and minimum valuve of the flux. Pls even if you can give me the formulas I'll be able to solve the question. – user189315 May 19 '18 at 12:23
• @user189315: Please move your comments into the question and provide proper formatting. And of course, calculating the area of a circle is not considered prior research effort for solving an question like this. It seems you don't want to invest learning effort, when it hurts. But learning only works if it hurts. – Ariser May 19 '18 at 12:29

## 1 Answer

Back to the basics : $$\Phi = NBS\cos(\vec n,\vec B)\\\vec n \text{ is the normal vector of the surface you want to find the flux}\\$$

Let's call : $$\alpha = (\vec n,\vec B)$$

Because alpha can vary from zero to 90 degree, cosine alpha vary from one to zero. So : $$\Phi_{min} = 0\\ and\\\Phi_{max} = NBS$$ This can be done mathematically by analyzing function : $$\Phi(\alpha) = NBS\cos(\alpha)$$