There is one paper of three hours duration of 100 marks. The paper is divided into two parts. Part I consists of short answer questions. This part is compulsory. Part II consists of eight questions. You are required to answer five questions.

**1. Introduction to electricity.** Structure of atoms; the model atom, nucleus, electrons. Unit of charge; coulomb. Potential difference and electromotive force. Production of electricity by friction, magnetism and chemical action.

**2. Electric circuit.** Electric current I = Qt. Ampere as rate of flow of charge. Ohm's law as applied to a single resistance (V/I = R) and to a whole circuit (E/I = total R).

**3. Equivalence.** Cell groupings. Resistances in series and parallel. Resistivity; R = Pl/A. Calculation of resistance of wire. Temperature coefficient of resistance. Ammeter shunts; voltmeter multipliers; series ohmmeter.

**4. Work, power and energy.** Work and energy. The joule. E =V/t (QV). Unit of power and energy; the watt, the kilowatt, the watt-hour and kilowatt-hour. Use of wattmeter. Calculation of electrical energy and power. Local tariff system.

**5. Heating effect of an electric current.** Application of heating effect, e.g. heating appliances, filament lamps, electric welding, electric carbon arc, and use of fuses.

**6. Chemical effect of an electric current.** Electrolytes and non-electrolytes. Elementary phenomena of electrolysis, including the electrolysis of acidified water, and of copper (II) sulphate solution using copper or platinum electrodes.

The factors affecting the mass of substance liberated in electrolysis and the measurement of current by voltameter (coulometer). Primary cells; Leclanche cell; polarization; local action. Accumulators; construction and characteristics of lead-acid cell; techniques of testing and charging batteries; care and maintenance.

**7. Electromagnetism.** Simple phenomenon of magnetism. Ferromagnetic properties of iron and steel. Magnetic effect of an electric current. The magnetic field associated with a current flowing in a straight wire, a circular coil, and a solenoid.

Force on a current-carrying conductor in a magnetic field; the right-hand and corkscrew rules. Magnetic flux density. Permeability.

**8. Electromagnetic induction.** Phenomenon of electromagnetic induction. Faraday's law; Lenz's law. Induced e.m.f.; a straight conductor cutting flux; E = - dφ/dt = Blv. Self-inductance; E = - Ldi/dr. Mutual inductance; the induction coil.

**9. Elementary electrostatics.** Electric field; E = V/d. Capacitance and the factors affecting capacitance. Electric flux density; D = Q/A. Permittivity; m = D/E. Energy of charged capacitors in series and in parallel.

**10. Alternating current.** Generation of an a.c. with a single loop coil. Sinusoidal wave form. Peak values; r.m.s. values (Only ratios will be expected.) Simple a.c. circuits.

**11. Transformer.** Principle of the single-phase transformer, and iron loss (hysteresis and eddy current).

**12. Lighting.** Common types of lamps; candela, lumen, lux, lux meter (light-meter). Illumination and photometry. Gas-filled lamps and fluorescent lamp circuits; preheat, instant and rapid starts.