What Is the Induced EMF in the Coil?

Ling2
Messages
4
Reaction score
0
A solenoid of length 45 cm has 340 turns of radius 2.2 cm. A tightly wound coil with 16 turns of radius 4.4 cm is at the center of the solenoid. The axes of the coil and solenoid coincide. Find the emf induced in the coil if the current in the solenoid varies according to I=4.6sin(50∏t)A.

Answer: __________cos(50∏t) mV

Comments:
I can't seem to find the correct answer for the magnetic field of the solenoid.
The formula I use is:
B=0.5μ0nI(sinθ2-sinθ1)
The area to use for all equations is the area of the solenoid since it is the area of magnetic field lines felt by the coil.
The flux, denoted ∅ is: ∅=BAcosσ and σ=0o, therefore ∅=BA
and the EMF=-N(d∅/dt)=-NA(dB/dt)

I really appreciate any help, thank you!
 
Physics news on Phys.org
B on the axis and at the centre of a 'long' solenoid is given by B = \mu_{o}nI where n = number of turns/length of solenoid.
 
Last edited:
Assuming the solenoid is long an using that formula, my answer is wrong. Is there anything missing to the comments I added for solving this problem?
 
Can you show the working for dB/dt?
 

Thread 'Please tell me where I am going wrong in this integral'

##|\Psi|^2=\frac{1}{\sqrt{\pi b^2}}\exp(\frac{-(x-x_0)^2}{b^2}).## ##\braket{x}=\frac{1}{\sqrt{\pi b^2}}\int_{-\infty}^{\infty}dx\,x\exp(-\frac{(x-x_0)^2}{b^2}).## ##y=x-x_0 \quad x=y+x_0 \quad dy=dx.## The boundaries remain infinite, I believe. ##\frac{1}{\sqrt{\pi b^2}}\int_{-\infty}^{\infty}dy(y+x_0)\exp(\frac{-y^2}{b^2}).## ##\frac{2}{\sqrt{\pi b^2}}\int_0^{\infty}dy\,y\exp(\frac{-y^2}{b^2})+\frac{2x_0}{\sqrt{\pi b^2}}\int_0^{\infty}dy\,\exp(-\frac{y^2}{b^2}).## I then resolved the two...
View full post »

Thread 'Direction of the magnetic field of an oscillating charge'

Hello everyone, I’m considering a point charge q that oscillates harmonically about the origin along the z-axis, e.g. $$z_{q}(t)= A\sin(wt)$$ In a strongly simplified / quasi-instantaneous approximation I ignore retardation and take the electric field at the position ##r=(x,y,z)## simply to be the “Coulomb field at the charge’s instantaneous position”: $$E(r,t)=\frac{q}{4\pi\varepsilon_{0}}\frac{r-r_{q}(t)}{||r-r_{q}(t)||^{3}}$$ with $$r_{q}(t)=(0,0,z_{q}(t))$$ (I’m aware this isn’t...
View full post »

Thread 'Initial conditions for orbits around a wormhole'

Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
View full post »

Similar threads

Potential difference defined in non-conservative electric field
Replies
12
Views
1K
How Can I Simulate Induced EMF in a Coil Using Ansys Maxwell?
Replies
1
Views
2K
B Magnet inside a solenoid with current
Replies
7
Views
1K
Calculate inductance of finite Solenoid
Replies
1
Views
5K
I Magnetic field at a point along the solenoid's axis but outside the solenoid
Replies
5
Views
2K
Drop height of a magnet vs. induced EMF in a solenoid
Replies
41
Views
7K
B EMF induced by Bar Magnet falling through a Coil
Replies
3
Views
606
Calculating magnetic field outside a solenoid
Replies
15
Views
1K
I How induction works within a coil (nuances of it)
Replies
6
Views
2K
What is the Magnetic Field of a Long Solenoid?
Replies
3
Views
2K

Hot Threads

Recent Insights

Back
Top