To determine the internal resistance of a dry cell.

Material

,,« 2 1.5 volt D-cell

,,« 1 resistor

,,« voltmeter

,,« ammeter

,,« light bulb on a metal clip

,,« positive and negative connector wires

,,« circuit board

Methods

Refer to page 650 of the textbook ¡§Physics 11¡¨

Results

Experiment 1: I = 0.22A Emf = 3.17V Vs = 2.98 V

Emf = Vs + Ir

Ir = Emf ¡V Vs

Ir = 3.17 ¡V 2.98

Ir = 0.19

Ir = 0.19

(0.22) r = 0.19

r = 0.863 £[

Experiment 2: I = 0.27A Emf = 3.09V Vs = 2.89 V

Emf = Vs + Ir

Ir = Emf ¡V Vs

Ir = 3.09 ¡V 2.89

Ir = 0.20

Ir = 0.20

(0.27) r = 0.20

r = 0.74 £[

Experiment 3: I = 0.11A Emf = 3.05V Vs = 2.96 V

Emf = Vs + Ir

Ir = Emf ¡V Vs

Ir = 3.05 ¡V 2.96

Ir = 0.09

Ir = 0.09

(0.11) r = 0.09

r = 0.81 £[

Experiment 4: I = 0.15A Emf = 3.00V Vs = 2.96 V

Emf = Vs + Ir

Ir = Emf ¡V Vs

Ir = 3.00 ¡V 2.96

Ir = 0.04

Ir = 0.04

(0.15) r = 0.04

r = 0.53 £[

Results in a Chart:

Experiment

Current

(I)

Electromotive Force

(Emf))

Terminal Voltage

(Vs)

Missing Voltage

(Ir)

Resistance (r)

1. 0.22 A 3.17 V 2.98 V 0.19 V 0.863 £[
2. 0.27 A 3.09 V 2.89V 0.20 V 0.74 £[
3. 0.11 A 3.05 V 2.96 V 0.09 V...