# Emf of a single loop wire around a solenoid

#### imatreyu

Sorry, the title is wrong. Should be "magnetic flux" of a single loop wire around a solenoid.

1. Homework Statement

A solenoid 4 cm in diameter and 20 cm in length has 250 turns and carries a current of 15 A. It is surrounded by a loop of wire 10 cm in diameter. The loop is positioned perpendicular to and centered on the axis of the solenoid. Find the magnetic flux through the loop of wire. (The field outside of the solenoid is small enough to be negligible.)

2. Homework Equations

E= N*A*B*w*sinwt ???

3. The Attempt at a Solution

I don't know where to start...at all. How is there even an emf in the loop if the field around the solenoid is negligible?

Last edited:
Related Introductory Physics Homework Help News on Phys.org

#### ideasrule

Homework Helper
There's no EMF, but the question is asking for the flux. What's the definition of flux?

#### imatreyu

flux is BAcostheta.

I'm confused on what to use for B. . .since there's no field created by the solenoid.

#### Caramon

Are you sure the solenoid doesn't create a magnetic field?

#### imatreyu

Actually. . . if someone could check my work:

B= 4pi x 10^-7 * 1400 turns * 15 A
= .0264 T

flux = BA cos theta
=.0264 T * (.0025 pi m^2)
=2.0735 x 10^-4 T*m^2

Answer = 2.0735 x 10^-4 T*m^2

Last edited:

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving