Magnetism - Quick solenoid question

  • Thread starter Thread starter thehammer
  • Start date Start date
  • Tags Tags
    Magnetism Solenoid
AI Thread Summary
A user calculated the magnetic field B inside a 200-turn solenoid but initially arrived at an incorrect answer of 7.28x10^-5 T instead of the expected 0.3 mT. The user realized they mistakenly used the wrong current value from a different problem. After correcting the current to 0.29A, they were able to resolve the confusion. The discussion highlights the importance of using accurate values in calculations for magnetic fields in solenoids. Accurate input is crucial for obtaining the correct results in physics problems.
thehammer
Messages
15
Reaction score
0

Homework Statement


A 200-turn solenoid having a length of 25cm and a diameter of 10cm carries a current of 0.29A. Calculate the magnitude of the magnetic field B inside the solenoid.


Homework Equations


B = \mu0ni


The Attempt at a Solution


Well, I plugged the numbers into the equation and got 7.28x10^-5 T as the answer. However, this is wrong. The correct answer is meant to be 0.3 mT. I can't see where I've gone wrong because the magnetic field inside a solenoid is meant to be independent of its dimensions, right?

EDIT: I found the number of turns per unit length, then put that into the equation and still get the wrong answer. I'm confused.

B = 4\pix10-7 Tm/A x (200/0.25) x 7.5A = 7.28x10^-5.

I've no idea why I get that. Maybe the diameter has some significance that I haven't managed to see yet.
 
Last edited:
Physics news on Phys.org
Show exactly what you plugged in for each factor.
 
thehammer said:
A 200-turn solenoid having a length of 25cm and a diameter of 10cm carries a current of 0.29A.
...
B = 4\pix10-7 Tm/A x (200/0.25) x 7.5A = 7.28x10^-5.
Looks to me like you are using the wrong current.
 
Oops. I apologise for wasting time. I used a current from a different question by accident :).
 
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanged mass'

Thread 'A cylinder connected to a hanged mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Calculating magnetic field outside a solenoid
Replies
15
Views
1K
Why are the effects of a magnetized material neglected in this case?
Replies
5
Views
2K
How Do You Calculate the Magnetic Field Inside a Solenoid?
Replies
2
Views
1K
Understanding self-inductance in a solenoid.
Replies
3
Views
1K
Current in circular wire surrounding infinite solenoid in a circuit
Replies
7
Views
1K
Electron in a time variable magnetic field
Replies
5
Views
1K
{ help } Calculating the B-field at the center of a solenoid
Replies
1
Views
2K
Calculating Induced EMF in a Larger Solenoid Slipped Over Another Solenoid
Replies
5
Views
2K
Calculting the length of a solenoid
Replies
7
Views
10K
Magnetization of the core of a long solenoid
Replies
5
Views
2K

Hot Threads

Recent Insights

Back
Top