Experimental report 2 Measurement of magnetic field Inside a solenoid with finite length môn Vật lý đại cương 2 | Học viện Công Nghệ Bưu Chính Viễn Thông

Experimental Report 2 MEASUREMENT OF MAGNETIC FIELD
INSIDE A SOLENOID WITH FINITE LENGTH
Verification of the instructors Class ID: 746171 Group: 3
Name: Đinh Quang Hiển Student ID: 20224281
I. Experiment Motivations
- Investigate the magnetic field at a position along the axis of solenoid
- Investigate the relationship between the magnetic field and the current through the solenoid II. Experimental Result
1. Investigation of the magnetic field at the position along the axis of solenoid – B(x) I=0.2 (A) x (cm) B (mT) x (cm) B (mT) x (cm) B (mT) 1 0.74 11 0.99 21 0.99 2 0.87 12 0.99 22 0.98 3 0.91 13 0.99 23 0.98 4 0.95 14 0.99 24 0.97 5 0.96 15 0.99 25 0.96 6 0.97 16 0.99 26 0.95 7 0.98 17 0.99 27 0.92 8 0.98 18 0.99 28 0.87 9 0.99 19 0.99 29 0.75 10 0.99 20 0.99 30 0.51
2. Measurement of the relationship between the magnetic field and the current through the solenoid – B(I) x = 15 (cm) I (A) B (mT) 0.15 0.77 0.2 0.97 0.25 1.23 0.3 1.44 0.35 1.63 0.4 1.85 0.45 2.11 0.5 2.34 0.55 2.57 0.6 2.82
3. Comparison of experimental and theoretical magnetic field I = 0.2 (A) x (cm) B (mT) 0 0.49 15 0.99 30 0.49 III. Data Analysis
1. Relationship between the magnetic field and the position of the probe inside the solenoid
Error bar: vertical 2ΔB=0.02 (mT) Comment:
The chart shows that the magnetic field reaches a maximum and remains stable at the center of
the solenoid, then gradually decreases and plummets near the ends. This pattern is expected, as
the magnetic field is strongest in the central region where the field lines are concentrated and
parallel then gradually decreases near the edges, which aligns with the theoretical behavior of
solenoid-generated magnetic fields.
2.Relationship between the magnetic field and the applied voltage
Error bar: vertical 2ΔB=0.02 (mT) Comment:
The graph shows that the magnitude of the magnetic field and the voltage has a linear
relationship. But in this case, the resistance is unchanged, so the current also has linear
relationship with the voltage. So, we can see that relationship between the magnetic field and the applied current is also linear
3. Comparison of experimental and theoretical magnetic field We have: B=μ0μr
2. I .n0(cosγ1−cosγ2) In this case, μ1=1 n0=NL=750 300×10−3=2500 I0=I √2 0.4 = √2=0.28 (A) cosγ1=x√ R2+x2
cosγ2=−L−x √
R2+(L−x)2 R=D2=40.3 2=20.2(mm)
+) x=0 (cm):cos γ1=0,cosγ2=−0.998 B=μ0μr 2In0
(cosγ1−cosγ2 )=1.256×106
2×0.28×2500×
(0+0.998 ) ¿0.44 (mT )
+) x=15 (cm):cos γ1=0.991,cosγ2=−0.991 B=μ0μr 2In0
(cosγ1−cosγ2 )=1.256×106
2×0.28×2500× (0.980 0.995 + ) ¿0.87 (mT )
+) x=30 (cm ):cos γ1=0.998,cos 0 γ2= B=μ0μr 2In0
(cosγ1−cosγ2 )=1.256×106
2×0.28×2500× (0.998 0 − )=0.44 (mT )
Comparison between theoretical values and experimental values: x (cm) Btheoretical (mT) Bexperimental (mT) 0 0.49 0.44 15 0.99 0.87 30 0.49 0.44
Compare with the obtained result in the experiment:
The result from the experiment is approximately close to the theoretical values. The difference is
due to the uncertainty of the instruments used. N (V) D (mm) L (mm) Solenoid 750 40.3 300 Coil 100 30 3