Inductance of a coil for a given emf and current change

In summary, the inductance of the coil is -0.51 H, which is a positive value and in line with Lenz's Law. The equation used to calculate this value was E=-M(delta I)/(delta t), and the given values were 2.50V for EMF, 31.0 mA and -28.0 mA for the current, and 12.0 ms for the time. This means that the induced EMF opposes the increasing current, resulting in a negative value for M.
  • #1
jena
74
0
Hi,

My Question:

What is the inductance of a coil if the coil produces an emf of 2.50V when the current in it changes form -28.0 mA to 31.0 mA in 12.0 ms?

For this I know I will need to use this equation:

E=-M(delta I)/(delta t)

My problem is that I was wondering if coming up with a negative inductance is alright.

Thank You :smile:
 
Physics news on Phys.org
  • #2
No. The inductance is positive. The induced EMF opposes the increasing current (Lenz's Law) which means that E must be negative (-2.50 V) in your example.
 
  • #3
So this work is fine then

E=-M(delta I)/(delta t)
2.50 V=(-M((31*10^-3 A) - (-28*10^-3 A)))/(12*10^-3 s)
2.50 V= -M(4.92 A/s)
-M=.51 H
M=-.51 H

Thank You:smile:
 

1. What is inductance and how does it relate to a coil?

Inductance is a property of an electrical conductor that describes its ability to produce an electromotive force (emf) when the current through it changes. In a coil, inductance is caused by the magnetic field that is generated when current flows through the wire.

2. How is the inductance of a coil calculated?

The inductance of a coil can be calculated using the formula L = μN²A/l, where L is the inductance in henries, μ is the permeability of the core material, N is the number of turns in the coil, A is the cross-sectional area of the coil, and l is the length of the coil.

3. Can the inductance of a coil change?

Yes, the inductance of a coil can change depending on factors such as the number of turns, the cross-sectional area, the core material, and the position of the coil. It can also be changed by adding or removing ferromagnetic materials near the coil.

4. What is the relationship between inductance, emf, and current change in a coil?

The inductance of a coil is directly proportional to the emf generated and the rate of change of current. This means that a larger inductance will result in a larger emf and a larger current change.

5. How does the inductance of a coil affect its performance in an electrical circuit?

The inductance of a coil can affect the performance of an electrical circuit in several ways. It can cause delays in current changes, create voltage drops, and limit the flow of high-frequency currents. It can also be used to store energy and create oscillations in circuits.

Similar threads

  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
987
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Electromagnetism
Replies
16
Views
995
  • Introductory Physics Homework Help
Replies
8
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
1K
Back
Top