Lesson 8.10 • NIE Practical Handbook: Experiments 30, 31, 32, 33, 34, 35Interactive Simulation

Current Electricity Practicals Hub

Complete suite of syllabus practicals: Exp 30 (V-I characteristics of conductor/diode), Exp 31 (internal resistance by voltmeter-ammeter), Exp 32 (resistance & resistivity by Meter Bridge), Exp 33 (temperature coefficient of resistance by Meter Bridge), Exp 34 (comparison of EMFs by Potentiometer), and Exp 35 (internal resistance of a cell by Potentiometer).

Marking a lesson complete represents finishing your study of the topic; it does not denote tested mastery.

Learning Objectives

Perform standard syllabus procedures for experiments 30 to 35 with live circuits, table data capture, and graph plotting.

Syllabus Topic Outline

NIE Practical Handbook: Experiments 30, 31, 32, 33, 34, 35

1Experiment 30: V-I Characteristics of Ohmic Conductor & Diode
2Experiment 31: Determination of Internal Resistance & EMF (V-I method)
3Experiment 32: Resistance & Resistivity of a Wire using Meter Bridge
4Experiment 33: Temperature Coefficient of Resistance using Meter Bridge
5Experiment 34: Comparison of EMFs of Two Cells using Potentiometer
6Experiment 35: Determination of Internal Resistance of a Cell using Potentiometer

A/L Physics Laboratory: Unit 8 Current Electricity Practicals Hub

Official NIE A/L Physics Practical Handbook Investigations (Experiments 31, 32, 33, 34): Dry Cell EMF & Internal Resistance, Metre Bridge Resistance & α, Potentiometer EMF Comparison, and Potentiometer Internal Resistance.

Determination of EMF and Internal Resistance of a Dry Cell (Exp 31)

Physical Principle & Governing Equations

Terminal potential difference V and discharge current I follow: V = E - I r. Plotting V versus I yields a straight line with y-intercept equal to EMF (E) and negative slope equal to internal resistance (-r).

V = E - I · r ⟹ Slope = -r, Intercept = E

Required Laboratory Apparatus

1.5 V dry cell, slide-wire rheostat (0–50 Ω), precision DC ammeter (0–1 A), DC voltmeter (0–3 V), plug switch, insulated connecting leads.

Experimental Observations & Data Table (Discharge Characteristics)

Discharge Current I (A)	Terminal Voltage V (V)	Calculated r = (E - V) / I (Ω)
0.10	1.40	1.00
0.20	1.30	1.00
0.30	1.20	1.00
0.40	1.10	1.00
0.50	1.00	1.00

Derived Experimental Result:

Derived EMF E = 1.50 V, Internal Resistance r = 1.00 Ω (Linearity R² = 1.000).