(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The problem can be found http://www.drewett-gray.co.uk/alevel/ff&e/papers/ffe_04_Jun.pdf" [Broken] (page 10 and 11)Question 4 part B i and ii

Mark Scheme if needed http://www.drewett-gray.co.uk/alevel/ff&e/papers/FFE_04_Jun_MS.pdf" [Broken]

2. Relevant equations

Faradays law: The induced emf is directly proportional to the rate of change of flux linkage.

Induced EMF = flux change/time

Induced EMF = Blx/t = Blv

3. The attempt at a solution

Question 4 Part B)i

I have attempted this by following the method of a similar problem in my revision guide.

So after 0.2 seconds the coil enters the field...

Information I have:

N=1250

B=0.032 T

V=0.10 ms^-1

Induced EMF = Blv*N = 0.032*0.02*0.1*1250

=0.08 = 80mV as required

I've used this because (l*v = l * x/t which is the area cut per unit time). I know it got the right answer but I'm not sure if my method is legitimate or not.

Part B ii)

This part has been giving me real trouble.

The way I understand it there will be no reading on the voltmeter until 0.2 seconds because the coil has not entered the field.

I'm not sure what happens when it enters the field, but I think the voltage will increase as the coil enters the field, because more and more coil is cutting the field per unit time. Then once all the coil is in the field it will be constant for a while, and then will decrease as the coil leaves the field.

However the markscheme talks about having some graph in the negative region, and I'm not sure why this should be the case.

Another thing I was thinking was trying to work out the voltage at certain times to get a rough idea of the shape of the graph.

Thanks

I Like Number

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: A-level Physics - Faradays Law and Electromagnetic Induction

**Physics Forums | Science Articles, Homework Help, Discussion**