Physics Practical - Motor effect HELP (1 Viewer)

[Shoaiblifts]

A bar magnet is placed on an electronic scale. Two retort stands are placed on opposite sides of the scales that are connected to two boss heads. A conducting wire will be placed between the two retort stands, by hanging them through the boss heads (with high tension so as to ensure an accurate 90 degree angle). This conducting wire is connected to a variable resistor, an ammeter and a transformer to complete a circuit. (Note: i made it sound like one wire, when its actually quite a few). Once a current runs through the conducting wire, as the magnetic field and direction of the current are perpendicular to each other, a maximum force will be experienced by the conductor. This will either increase or decrease the mass of the magnet as recorded by the electronic scale. By varying the resistance, and hence the independent variable, the current is changed. From the results obtained, we must calculate the value for magnetic field strength and hence graph Force vs Current. Should be a linear relationship, however whether it is linear or not gives me material to talk about reliability, validity and accuracy.

What are some errors and improvements that could be made to this investigation?

Thanks Peeps.

 

[1008]

A bar magnet is placed on an electronic scale. Two retort stands are placed on opposite sides of the scales that are connected to two boss heads. A conducting wire will be placed between the two retort stands, by hanging them through the boss heads (with high tension so as to ensure an accurate 90 degree angle). This conducting wire is connected to a variable resistor, an ammeter and a transformer to complete a circuit. (Note: i made it sound like one wire, when its actually quite a few). Once a current runs through the conducting wire, as the magnetic field and direction of the current are perpendicular to each other, a maximum force will be experienced by the conductor. This will either increase or decrease the mass of the magnet as recorded by the electronic scale. By varying the resistance, and hence the independent variable, the current is changed. From the results obtained, we must calculate the value for magnetic field strength and hence graph Force vs Current. Should be a linear relationship, however whether it is linear or not gives me material to talk about reliability, validity and accuracy.

What are some errors and improvements that could be made to this investigation?

Thanks Peeps.

To start with, use a digital scale, not a non-digital one.

I guess one of the most important suggestions to this experiment would be to use a VERY strong magnet and a solenoid with lots and lots of coils because on such a small scale, the current passing through the wire may not be enough for any change in weight to be recorded by the scales. You might notice a change in mass to 1 decimal place, but the actual difference could be larger/smaller depending if the machine has rounded the actual weight up or down.

Make sure you repeat the experiment with different magnets, currents and coils of wires in order to ensure that the linear relationship you do (or don't) get is consistent throughout your experiments. If it's consistent but not theoretically accurate, you could comment on there being a possible human error or defect in some of the equipment used (e.g. scales were faulty). If it's inconsistent, you could say talk about the accuracy of the experiment (e.g. the lack of sensitivity of the scales to be able to record the weight of the magnet to higher decimal places).