Experiment 6.1: Earth’s magnetic field Lab Date: 07/18/2020 Report Date: 07/24/2020 Melany Rodriguez TA: K alpani Nisan sala Udeni Ga lpayage Do na Sectio n 004 PURPOSE The purpose of this ex perim ent is to obt ain the horizont al component of the earth’s magn etic field (Bh) by measuring the period of oscillation of a bar magnet in a k nown field. THEORY EXPERIMENTAL METHOD Materials: PASCO Helmholtz (EM -6711 and EM -6715 N=200, radius R=10.5cm ), bar magnet, photogate (ME -9204A), resistor ~ 40Ω ( 2W), PASCO 850 interface, computer. Measurement 1: 1. In the Controls Palette (at the bottom of the W orkbook Page) sele ct “Keep M ode”. 2. In the Controls P alette se t sampl ing rate fo r Output Volt age-Current Sen sor to 1.0 kHz. 3. In the T ools Palette, click ”Signal Generator ” button to open the Si gnal Generator panel. Click on “850 Output 1 ” and make the following sel ections: (a) Wave form: DC (b) DC Volt: 0V (c) Off 4. The le ft side of Page #1 is blocked by the “Signal generator panel ”. Click the red pin at the upper -right corner of the T ools panel, then the full Page #1 is displayed on the right side of the “Signal generator pane l”. 5. Fine adjus tment of the bar magnet relative to the photogate (a) Adjust the position of the phot ogate to let one end of the magnet crossing the dashed vertical line conn ecting the light and rec eiver of the photo gate shown in Fig. 3, so that the ph otogate indicator (light) is on and off when the bar magnet passes through the photogate. (b) Make sure the bar magnet oscillates horizontally (about 30 -45 degrees). 6. On Si gnal Generator panel check DC Volt: 0V , then click “On” to turn of the DC power supply . 7. Click “Preview ” (at the bottom -left of P age #1), the data of vol tage, current and period appear in the Table. 8. The oscillation of the bar magnet and the da ta shown in the Table become stable after the bar magnet makes 2~3 c omplete oscillation cycles. Click “Keep Sample ” (at the bott om-
left of Page #1) to s tore the data. 9. Increase the DC voltage 1V each time and repeat steps 5 and 8. The final output voltage from the DC power supply is 10V, so total 11 data point s (0v to 10V) are t aken an d stored. The data of 1/ T2 vs I c are plotted in gr aph display window on Page #1. 10. When the data at 10V have been stored, click “Stop ” (at the bottom -left of P age #1) to end the data collection. 11. Data display If the curve does not fill the gr aph window , click on t he Scale -to-Fit tool at the top -left corner of the graph window.
left of Page #1) to s tore the data. 9. Increase the DC voltage 1V each time and repeat steps 5 and 8. The final output voltage from the DC power supply is 10V, so total 11 data point s (0v to 10V) are t aken an d stored. The data of 1/ T2 vs I c are plotted in gr aph display window on Page #1. 10. When the data at 10V have been stored, click “Stop ” (at the bottom -left of P age #1) to end the data collection. 11. Data display If the curve does not fill the gr aph window , click on t he Scale -to-Fit tool at the top -left corner of the graph window.
