Question

Please help me answer this 3-part question based on the information that follows, showing work when helpful:

a. What is the effective resistance of the resistors you used for number 3?

b. Which of your measurements had the smallest relative uncertainty?

c. Batteries have an internal resistance, which we have not considered in the lab. How would the internal resistance of your battery affected your calculations for part a?

R1=10 KiloOhms, R2=2.2 KiloOhms, R3=1 KiloOhm, E1 and E2 each equal 1.5 V

1. Construct the circuit shown in Figure 1. Use the largest resistor in your pack for Rı, the second largest resistor for R2, and the third largest resistor for R3. Use a single AA battery for Ej. Measure the voltage across Rį and R2 while the circuit is connected to the battery. You can calculate what this voltage is if R1, R2, R3, and Ej are known. Measure each of these (you may use last week's lab for the resistance) and calculate what the voltage across R1 and R2 should be. Compare your measured voltages to these calculations. 2. Construct the circuit shown in Figure 2 Use the largest resistor in your pack for R1 and the second largest resistor for R2. Use one AA battery for Ej and a second AA battery for E2. Measure the potential difference between the points cand f. You can calculate what this voltage is if R1, R2, El, and E2 are known. Measure each of these (you may use last week's lab for the resistance) and calculate what the voltage between c and f should be. Compare your measured voltage to your calculation. 3. Construct the circuit shown in Figure 3 Use the largest resistor in your pack for Ri, the second largest resistor for R2, and the third largest resistor for R3. Use a single AA battery for Ej. Measure the current through the battery and R2. You can calculate what these currents should be if Ri, R2, R3, and Ei are known. Measure each of these (you may use last week's lab for the resistance) and calculate what the current through the battery and R2 should be. Compare your measured currents to your calculations. 4. Construct the circuit shown in Figure 4 Use the largest resistor in your pack for R1 and the second largest resistor for R2. Use one AA battery for Ej and a second AA battery for E2. Measure the current through the wire connecting points c and f. You can calculate what this current should be if R1, R2, Ej and E2 are known. Measure each of these (you may use last week's lab for resistance) and calculate what the current should be. Compare your measured current to your calculation.

Fig 1:

Fig 2:

Fig 3:

Fig 4:

Answer 1

③ part Ri= loke R2 = 2.2k Rz = 1 kr bem lo R3 R2 is the current flowing from battery, since R, and R₂ are connected in parallel. MT R3 Rill R2 - W effective resistance - Reff = R₂ + (R, 11R2) It / 10x2.2 ) Tot 202 It 22 - +18 2.8kr - 218x103 n current through battery E, - 12.2 "= & Reff 2088103 = 01833x103A = 0.833mA current through R2 , using cussent deveder rule =R xi k+RX 10 0,833 lot 212 X X 0.833 22.2 = 0.683mA