Electromagnetic Induction? HELP

AI Thread Summary
The discussion centers on three problems related to electromagnetic induction. In the first scenario, a horizontal loop moving through a vertical magnetic field results in an induced emf that is not constant, leading to confusion about the correct answer. The second problem confirms that doubling the number of turns in a solenoid while halving the current increases its self-inductance by four times. The third scenario involves a light bulb and an air-core coil, where inserting an iron core after an hour leads to an unexpected outcome, with participants seeking clarification on the results. Overall, the thread emphasizes the need for a deeper understanding of induced emf and its calculations.
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Electromagnetic Induction!? HELP !

Homework Statement


1.
A single horizontal loop of wire is moving in a horizontal plane at a constant speed across a uniform vertical magnetic field that "fills" and surrounds the loop. The emf induced across its terminals will be ...??
the answer was "none of these" =not constant, negative, positive...
What can be the answer then??!

2.
A solenoid is physically altered by doubling the number of turns it has while halving the current through it, leaving everything else unchanged.
Answer: its self-inductance is four times greater.

3.
A small light bulb is in series with an air-core coil and a dc power supply such that the lamp glows brightly. An iron core is then inserted into the coil, and an hour later the lamp...!??
The answer was none of these...

what can be the answer then??!



Please HELP ! ASAP ! Thank you for your kind help!
 
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None of what?

What have you tried? If you're given some answer choices, which one, if any, seems correct to you, and why?
 


For 1 and 3,, the answer was none of these..for 1 not positive, constant..etc.

SO, I was wondering what would happen(answer)?What would be the answer?

I now understand number 2..
 


For (1), use the equation for induced EMF. (You should have included this as a Relevant Equation when you submitted your questions.)
 

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