Practical ELectromagnet

Date:                    Construction and Testing of an Electromagnet      Grade:10

Brief note on theory

Whenever an electric current flows through a conductor their will always be an associated magnetic field produced. This process of an conductor to propagate magnetic fields due to a current applied to it, is called electromagnetism. The magnetic field lines can be considered as a magnetic force field. Thus any magnetic materials within this field’s proximity will experience a magnetic force acting on it. Electromagnetism is the principal behind  electromagnets .  

Electromagnetic construction

Materials Provided.

Variable D.C. voltage power supply, 200 ohm resistor, connection leads, crocodile leads, 22-26 gauge copper wire,  Ammeter (1A-3 A),  ferromagnetic core (nail)  Voltmeter, paper clips, electronic balance (2D.P.), sandpaper

Method :

Use the ferromagnetic or steel(nail) material to act as a core, and wrap around it the copper wire making about  30 -100 turns.  Making sure that both ends of  copper wire  have had their insulation removed and connect to variable voltage power supply . Place  paper clips near the electromagnet to see if there is any attractive force acting them .

(2) Construct the circuit shown below      Resistor

              Variable D.C .Voltage Supply

               -

                 +

(3)Count the number of turns (N) that make  up the coil and measure current flowing through it. Place paper clips near electromagnet  count how many paper clips are attracted to it (find mass of paper clips using electronic balance )Repeat this process 6 times increasing the current for each  new measurement taken keeping (N) constant.  Record values in table given.

(4) Repeat the above but this time keep the current constant but vary the number of coil turns (N).

(5) Measure coli length (L) with a ruler

(6) Calculate cross –sectional area of coil

(7) Record all your values and place in table provided below

(8) Plot graphs of (1) Force (y axis)  /Current(x axis)  (2) Force (y axis)/N (x axis)

Results Table

 (9)  Given Force (F) =  (NI)^2 ( m ) (A/2L^2) and your recorded values above  determine an average value for the constant (m)

Average value of  (m) =  ----------------------------------------------

Conclusion and Reflection