Would this be the correct formula?

Question

If an experiment required you to measure the emf in a solenoid by changing :

1. The number of magnets
2. the distance between the solenoid and the magnet
3. the relative motion or velocity

Would the correct formula to calculate the emf be :

ε = BLV

where :

B = magnetic field

L = distance between the solenoid and the magnet

V = Changing velocity

If not, what would be the correct formula ?

AND when reading off a galvanometer , if the pointer is goes towards the left do I record my results as - ? ( e.g -2) ?

Thank you

Answer 1

Hi Jimmy K.,

you didn't include a description of your experiment, so it's difficult to know what the desired output expression may be. BUT -- if you were doing the experiment, and changing each of these three variables, one at a time, over a significant range, you should be able to construct the proper expression putting them together. It will be the product of the three individual functions for each variable, most likely. Caution: it may only apply over the experimental variable range!

But also, how do you know that the magnetic field is necessarily linearly proportional to the number of magnets employed? I bet it isn't ....

Yes, just keep your convention constant about which direction of galvanometer needle twitch is positive, and which negative.

-- Cheers, --Mr. d.