# Thread: Checking my M&G Prac Report?

1. ## Checking my M&G Prac Report?

Hi guys,

We have to finish this prac report for homework and was just wondering is someone could check my answers to see if I'm on the right track.

Ok so our experiment was observing Faraday's law (we moved a magnet in and out of a coil and measured change in flux and current through a datalogger).

Aim: To observe Faraday’s experiment, known as induction. It demonstrates that relative movement between the magnet and the coil generates an induced current, due to a change in flux.

Hypothesis: I believe that as the number of turns decreases, the induced current decreases. This can be seen through the formula

Apparatus: datalogger, voltage probe, plastic former, 3m copper wire, magnet, retort stand, boss head, clamp

Method:

Set up the apparatus as shown
Wind 16 turns CLOCKWISE onto the plastic former
Insert the magnet, measuring the magnitude and direction of the induced EMF
Wind a further 8 turns ANTICLOCKWISE, measure again
Wind another 8 turns ANTICLOCKWISE, measure again

Independent: The number of turns on the plastic former.

Dependent: The induced current formed by relative movement between the magnet and the coil.

Control Variables: The speed of the movement of the magnet in the coil.

Past tense

3. ## Re: Checking my M&G Prac Report?

Originally Posted by Queenroot
Past tense
ok do you think the general ideas are right though?

4. ## Re: Checking my M&G Prac Report?

Don't use "I believe"

5. ## Re: Checking my M&G Prac Report?

Originally Posted by luo_ge
Hi guys,

We have to finish this prac report for homework and was just wondering is someone could check my answers to see if I'm on the right track.

Ok so our experiment was observing Faraday's law (we moved a magnet in and out of a coil and measured change in flux and current through a datalogger).

Aim: To observe Faraday’s experiment, known as induction. It demonstrates that relative movement between the magnet and the coil generates an induced current, due to a change in flux.

Hypothesis: I believe that as the number of turns decreases, the induced current decreases. This can be seen through the formula

Apparatus: datalogger, voltage probe, plastic former, 3m copper wire, magnet, retort stand, boss head, clamp

Method:

Set up the apparatus as shown
Wind 16 turns CLOCKWISE onto the plastic former
Insert the magnet, measuring the magnitude and direction of the induced EMF
Wind a further 8 turns ANTICLOCKWISE, measure again
Wind another 8 turns ANTICLOCKWISE, measure again

Independent: The number of turns on the plastic former.

Dependent: The induced current formed by relative movement between the magnet and the coil.

Control Variables: The speed of the movement of the magnet in the coil.
- Never use first person in a prac report.
- Shorten the aim by saying, "To demonstrate Faraday's law of electromagnetic induction using the relative movement between a magnet and a coil."
- When you say "seen through the formula", write the formula, don't just say the formula without giving it.
- For dependent, just say "magnitude and direction of induced current".
- Control variables you can add more stuff like same data logger, same plastic former, same magnet strength, etc.

6. ## Re: Checking my M&G Prac Report?

Originally Posted by pikachu975
- Never use first person in a prac report.
- Shorten the aim by saying, "To demonstrate Faraday's law of electromagnetic induction using the relative movement between a magnet and a coil."
- When you say "seen through the formula", write the formula, don't just say the formula without giving it.
- For dependent, just say "magnitude and direction of induced current".
- Control variables you can add more stuff like same data logger, same plastic former, same magnet strength, etc.
ok so we did a practice prac today and we were measuring voltage. so would the dependent variable be voltage then?

and how do you recommend graphing this?

/////// Sample 1: Sample 2: Sample 3: Average:
8 turns 0.027V 0.023V 0.029V 0.026V
16 turns 0.047V 0.045V 0.047V 0.046V
24 turns 0.047V 0.046V 0.049V 0.047V

7. ## Re: Checking my M&G Prac Report?

How do u think u shouold graph it

8. ## Re: Checking my M&G Prac Report?

Originally Posted by Queenroot
How do u think u shouold graph it
i tried to graph it as a line graph on excel but it just ends up as one line on the x-axis

9. ## Re: Checking my M&G Prac Report?

What did u use for each axis?

10. ## Re: Checking my M&G Prac Report?

Originally Posted by Queenroot
What did u use for each axis?
i put voltage on the y-axis and turns on the x-axis. since the independent variable has to be on the x-axis and the y-axis has to have your dependent variable.

Also do you think this statement is correct?:

As the number of coil turns on the plastic former increases, the voltage increases. This is because an increased number of coils would result in more flux lines, and therefore a greater change of flux. And a greater change of flux results in a greater induced current and therefore an increased voltage (still resistance remains constant).

11. ## Re: Checking my M&G Prac Report?

Originally Posted by luo_ge
i put voltage on the y-axis and turns on the x-axis. since the independent variable has to be on the x-axis and the y-axis has to have your dependent variable.

Also do you think this statement is correct?:

As the number of coil turns on the plastic former increases, the voltage increases. This is because an increased number of coils would result in more flux lines, and therefore a greater change of flux. And a greater change of flux results in a greater induced current and therefore an increased voltage (still resistance remains constant).
This isn't right, an current doesn't lead to an increased voltage. The change in flux causes an induced emf which GIVES RISE to a current (Lenz's Law). So from this we can see that higher voltage (emf) causes higher current as V is proportional to I in V=I/R.

Also, Faraday's law - Emf = -n * delta flux / delta time, this shows that the more change in flux (more loops cutting flux lines) the more emf, which is the same as voltage.

12. ## Re: Checking my M&G Prac Report?

Originally Posted by pikachu975
This isn't right, an current doesn't lead to an increased voltage. The change in flux causes an induced emf which GIVES RISE to a current (Lenz's Law). So from this we can see that higher voltage (emf) causes higher current as V is proportional to I in V=I/R.

Also, Faraday's law - Emf = -n * delta flux / delta time, this shows that the more change in flux (more loops cutting flux lines) the more emf, which is the same as voltage.
oh so is voltage the same as the rate of change in flux?

13. ## Re: Checking my M&G Prac Report?

Originally Posted by luo_ge
i put voltage on the y-axis and turns on the x-axis. since the independent variable has to be on the x-axis and the y-axis has to have your dependent variable.

Also do you think this statement is correct?:

As the number of coil turns on the plastic former increases, the voltage increases. This is because an increased number of coils would result in more flux lines, and therefore a greater change of flux. And a greater change of flux results in a greater induced current and therefore an increased voltage (still resistance remains constant).
And did you average the trials

14. ## Re: Checking my M&G Prac Report?

Originally Posted by sarkar_as
oh so is voltage the same as the rate of change in flux?
Voltage is basically equivalent to emf

15. ## Re: Checking my M&G Prac Report?

Originally Posted by pikachu975
This isn't right, an current doesn't lead to an increased voltage. The change in flux causes an induced emf which GIVES RISE to a current (Lenz's Law). So from this we can see that higher voltage (emf) causes higher current as V is proportional to I in V=I/R.

Also, Faraday's law - Emf = -n * delta flux / delta time, this shows that the more change in flux (more loops cutting flux lines) the more emf, which is the same as voltage.
Isn't the formula V=IR and not V=I/R?

And does emf induce current?

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