Physics P42 Discussion

[TANJIAHOU]

You use voltmeter to measure emf in a coil the same way you measure emf of cell. The pd across the voltmeter will be similar to the actual emf because it has very high resistance. I = E/R , V = IR.
Its really both series and parallel in a simple circuit

 

[nightmaressana]

But the coil was moving bro, it was taken away from the straight conductor
I wrote that voltmeter was connected in series so bad suggestion can it be correct?

Yes, the coil was moving. It Was taken away from the straight conductor.

 

[TANJIAHOU]

Of course it was taken away from the straight wire. The questiom stated that the coil was positioned at distances x from the wire to get data to calculate the magnetic flux density. It didnt state that he moved the wire with a speed.

 

[nightmaressana]

Of course it was taken away from the straight wire. The questiom stated that the coil was positioned at distances x from the wire to get data to calculate the magnetic flux density. It didnt state that he moved the wire with a speed.

But that also didnt mean that he didnt move the wire at all. Even if there is a little change in flux, emf is induced. Im just stating that.

 

[pakiboy]

Of course it was taken away from the straight wire. The questiom stated that the coil was positioned at distances x from the wire to get data to calculate the magnetic flux density. It didnt state that he moved the wire with a speed.

Bro i have done similar questions in pastpapers where moving away the coil does induce an emf

 

[pakiboy]

But that also didnt mean that he didnt move the wire at all. Even if there is a little change in flux, emf is induced. Im just stating that.

What did you write about the suggestion then?

 

[pakiboy]

You use voltmeter to measure emf in a coil the same way you measure emf of cell. The pd across the voltmeter will be similar to the actual emf because it has very high resistance. I = E/R , V = IR.
Its really both series and parallel in a simple circuit

Bro if the current doesnt flow how are you going to get a reading of voltage

 

[TANJIAHOU]

Bro i have done similar questions in pastpapers where moving away the coil does induce an emf

I did all the past years from 2002 up to 2013. Emf is induced ONLY when there is a cutting of flux . I repeat, the question didn't say that the student moved the coil to get a reading. It was only given that readings were taken at certain distances, X. Voltmeter in series can't be the problem. Wow.. Current doesn't flow? There is a current dude.. And its very small.............................................................

 

[nightmaressana]

What did you write about the suggestion then?

Honestly, i dont remember.

 

[nightmaressana]

Bro i have done similar questions in pastpapers where moving away the coil does induce an emf

Yup, ive done pp too. It induces emf.

 

[TANJIAHOU]

Ask your teacher. See what he says.

Yup, ive done pp too. It induces emf.

 

[pakiboy]

I did all the past years from 2002 up to 2013. Emf is induced ONLY when there is a cutting of flux . I repeat, the question didn't say that the student moved the coil to get a reading. It was only given that readings were taken at certain distances, X. Voltmeter in series can't be the problem. Wow.. Current doesn't flow? There is a current dude.. And its very small.............................................................

Bro how are you going to reach at point x you definitely have to move the coil lol and if the current is very small then it is of no use

 

[nightmaressana]

I did all the past years from 2002 up to 2013. Emf is induced ONLY when there is a cutting of flux . I repeat, the question didn't say that the student moved the coil to get a reading. It was only given that readings were taken at certain distances, X. Voltmeter in series can't be the problem. Wow.. Current doesn't flow? There is a current dude.. And its very small.............................................................

He did move the coil. I remember this part.

Bro how are you going to reach at point x you definitely have to move the coil lol and if the current is very small then it is of no use

Tanijiahou, hes right. Pakiboy is absolutely correct.
I dont want to call my teacher every now and then.

 

[pakiboy]

He did move the coil. I remember this part.

Tanijiahou, hes right. Pakiboy is absolutely correct.
I dont want to call my teacher every now and then.

Guyz the paper is over we did our best now leave the rest to Allah and pray
Threshold for an a* will never go up from 190/260 so chill and rock the 52 paper tomorrow

 

[TANJIAHOU]

He did move the coil. I remember this part.

Tanijiahou, hes right. Pakiboy is absolutely correct.
I dont want to call my teacher every now and then.

I asked my teacher. I'm right. The voltmeter will show its own voltage drop.

 

[nightmaressana]

Checck november 2004 question. Similar to the question we were asked. Just the setup.

I asked my teacher. I'm right. The voltmeter will show its own voltage drop.

 

[nightmaressana]

I asked my teacher. I'm right. The voltmeter will show its own voltage drop.

So you're saying the voltmeter will Not show the emf induced?

 

[TANJIAHOU]

Checck november 2004 question. Similar to the question we were asked. Just the setup.

// The average magnetic flux density B through the coil varies with the distance x between the
face of the magnet and the plane of the coil. // This is calculated by using the formula of magnetic flux density around a long straight wire, B = mu0*i/2*pi*x; not from calculations involving induced emf in the coil.

//The coil is moved along the axis of the magnet so that the distance x changes from
x = 5.0 cm to x = 15.0 cm in a time of 0.30 s. // Did the student state something like this??

You are assuming that the student stated the constant speeds at which he moves the coil.

 

[pakiboy]

// The average magnetic flux density B through the coil varies with the distance x between the
face of the magnet and the plane of the coil. // This is calculated by using the formula of magnetic flux density around a long straight wire, B = mu0*i/2*pi*x; not from calculations involving induced emf in the coil.

//The coil is moved along the axis of the magnet so that the distance x changes from
x = 5.0 cm to x = 15.0 cm in a time of 0.30 s. // Did the student state something like this??

You are assuming that the student stated the speed at which he moves the coil.

It was just a suggestion bro

 

[nightmaressana]

Im

// The average magnetic flux density B through the coil varies with the distance x between the
face of the magnet and the plane of the coil. // This is calculated by using the formula of magnetic flux density around a long straight wire, B = mu0*i/2*pi*x; not from calculations involving induced emf in the coil.

//The coil is moved along the axis of the magnet so that the distance x changes from
x = 5.0 cm to x = 15.0 cm in a time of 0.30 s. // Did the student state something like this??

You are assuming that the student stated the speed at which he moves the coil.

not assuming anything. I told you i dont remember my answer but a friend of mine stated that this method was incorrect as speed wasnt measured. She justified it using this. So i think her answer is right.thats why im supporting pakiboy.