# True or False

cyprusx
The magnitude of the current depends on the rate at which the magnet is moving in and out of the solenoid.

True or false

Homework Helper
Have you considered flipping a coin?

Now you know you are expected to make some effort yourself. In this case, I assume you are talking about a generator consisting of a magnet moving inside a coil- You should have said that. What does your textbook say about generators? What formulas do you know for current?

semc
since voltage induced is proportional to the rate of change of B-field,i think magnitude is also dependent on it?

cyprusx
i really have no clue, I am a noob

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i really have no clue, I am a noob
Consider Faraday's Law together with Ohm's law.

cyprusx
man, i have too hand this in tomorrow and I am at risk of failing can you cut a guy a break

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man, i have too hand this in tomorrow and I am at risk of failing can you cut a guy a break

I will help you, but I am not going to give you the answer. However, if you do put some effort in, you will have the answer within minutes. Now, what is Faraday's law?

cyprusx
Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be "induced" in the coil.

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Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be "induced" in the coil.
Correct, this can be represented mathematically;

$$V=\frac{\Delta\Phi}{\Delta t}=\frac{\Delta (BA)}{\Delta t}$$

Next, what is ohm's law?

cyprusx
Ohm's law states that, in an electrical circuit, the current passing through a conductor is directly proportional to the potential difference applied across them provided all physical conditions are kept constant.

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Ohm's law states that, in an electrical circuit, the current passing through a conductor is directly proportional to the potential difference applied across them provided all physical conditions are kept constant.
And mathematically;

$$I = \frac{V}{R}$$

So, can you now combine the two equations?

As an aside, I do hope that you are taking the time to understand these laws and are simply not copying and pasting them directly from the internet.

cyprusx
how do you comine them

Staff Emeritus
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Substitute Faraday's law for the V in ohm's law.

cyprusx
cant you help a guy out

Hootenanny I am studying for a test right now that's in an hour i really don't have time.

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I will do the substitution for you, however, you must draw your own conclusions. So now we can say that;

$$I = \frac{\frac{\Delta (BA)}{\Delta t}}{R} = \frac{\Delta (BA)}{R\cdot\Delta t}$$

Now, if you change that rate at which you move the magnet through the coil, do any terms change in the above equation?

cyprusx
yes they do

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yes they do
So does the current change?

cyprusx
yes

so my initial question is False

cyprusx
or...

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The magnitude of the current depends on the rate at which the magnet is moving in and out of the solenoid.
If the current does change when you change the rate at which the magnet moves then the above statement is ____

cyprusx
true...

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true...

Sounds good to me

cyprusx
Hootenanny does the magnitude of the current depend on the strength of the magnet.

P.S because weave formed such a close friendship over these past hours do you think you might be able to answer my other question... pleaseeeeee

HalfManHalfAmazing
is this for real? you are studying for a test and can't combine 2 equations? is this grade 11 or something?

cyprusx
yeah....

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