# emf

1. ### is it correct to say?

is it correct to say; applied emf= 6V therefore, back emf= -6V ??
2. ### induced emf in a solenoid due to a rotating magnet

Hey, I have come up with an idea for my EEI to measure the emf induced in a solenoid by a rotating magnet when the solenoid is not directly above the magnet (such that the magnetic field is not uniform). Previously I had to perform an experiment where the solenoid was on axis (see picture) and...
3. ### Motional EMF: sign difficulties

Hi, I'm trying to understand how a moving conductor traveling with a constant velocity in a uniform magnetic field can produce an emf of -Blv where l is the length of the conductor AND have the positive charges stack up at the top. There seems to be some sort of contradiction that the top has...
4. ### Current of Electricity and Emf questions?

Can anyone help me with the following 2 questions. For the 1st question, I have no idea how to begin with it? For the 2nd one, it is either A or B but what is the difference? The field line still cuts the plane of the coil??
5. ### Motional EMF related question

A metallic rod is held horizontally along east-west direction, is allowed to fall under gravity. Will there be an EMF induced at its ends? Justify your answer. My answer - The magnetic field of Earth is constant and hence there is no magnetic flux change and hence no EMF. Friend's answer -...
6. ### How to find e.m.f and power of a given circuit.

I have unload a image of the circuit.
7. ### Is EMF generated in this special loop of wire

A square loop of wire is kept hanging upright and has 3 sides made of copper and the lower horizontal side made of iron. The loop has its surface normal to a uniform magnetic field B. The question is: If the loop is allowed to fall while fully immersed in this field B, will an EMF be generated...
8. ### Question about flux and emf inductance

In this context (also attached): http://i.imgur.com/baapO.jpg How do I know which direction the current points via the induced emf by the downward flux (as the wire moves)? I'm very confused with the flux causing/inducing emf stuff. I can tell which direction the current is in because the...
9. ### Finding magnitude of induced emf through Faraday's Law?

I am not sure how to approach this problem: A square copper loop, with sides of length 10.0 , is located in a region of changing magnetic field. The direction of the magnetic field makes an angle of 37.0 with the plane of the loop. The time-changing (increasing) field has the following time...
10. ### Which one will produce e.m.f?

Which one will produce e.m.f? (i)A circular coil placed in a non-homogenous magnetic field (ii)A circular coil moved with constant velocity in a homogenous magnetic field (iii)A circular coil moved with constant velocity in a non-homogenous magnetic field (iv)None of the above I'm...
11. ### induced emf

The flux through a loop at time t is given by Φm = Φ0e-t/T Wb. The induced emf at t = T/2 s is....?
12. ### Emf giving constant current

I'd like to know how it is possible for an emf to give constant current instead of constant voltage (like common batteries). Can you give some examples of them?
13. ### EMF vs p.d.

I've got a test tomorrow and i'm 90% sure this'll be on the test so i was wondering who could help me, i really don't understand the difference between P.D and EMF... Anyone able to explain it in simple layman's terms please? And the more technical jargon too if you don't mind Thx, //James~