Homework Help: Quick Conceptual Question on Lenz's Law

1. Apr 5, 2012

longcatislong

1. The problem statement, all variables and given/known data
A magnetic field is uniform throughout a region of space, but increases from 0 to 0.14 T in 2.4 s. A circular coil (of diameter 19 cm) is placed in a fixed orientation in this region such as to receive maximum flux. It takes 4171.91 turns to generate an emf of 6.9 V

What inherent property of the coil determines the degree to which it is able to fight the flux change, per Lenz's Law?

a) curent
b) EMF
c) Resistance
d) induced magnetic field

3. The attempt at a solution

I'm leaning toward saying that it's a) current. I know I dont' compeltley understand this yet, but I see nothing about inherent properties of coils in my book. All I've gleaned from my reading is that the current will always flow in the direction that opposes the change that caused it.

Can anyone confirm that I'm on the right track?

2. Apr 5, 2012

RK7

What happens to the coil to make it oppose the change in magnetic flux?

3. Apr 5, 2012

longcatislong

The coil? It makes a current that makes a field to oppose the external field...?

4. Apr 6, 2012

RK7

That's right. What affects the strength of the of the field the coil generates?

There probably won't be anything about "inherent properties of coils" in your book, but would you say the current in a piece of wire is an inherent property of it? A web definition of inherent says an inherent property is a "characteristic attribute".

5. Apr 6, 2012

longcatislong

So, the coil needs to generate a current in response to a changing external magnetic field. The current generated by the coil will in turn create an induced magnetic field. What affects the strength of the current/magentic field is the resistance of the coil... yes...?

6. Apr 6, 2012

RK7

I agree with that. Also note that the resistance is the only answer which is an inherent property of a coil. All the others depend on the environment you put the coil in.

7. Apr 7, 2012

binbagsss

Why is it exactly that the resistance is an inherent property of the coil, I would have thought that it would depend upon the temperature of the environment?