# Physics SS 3 Curriculum Guides – Simple A. C. Circult, Electric Field, Electromagnetic Field, Magnetic Fields and Gravitation Field

**THEME – FIELDS AT REST AND IN MOTION**

**TOPIC 1 – SIMPLE A.C. CIRCUITS**

**INSTRUCTIONAL MATERIALS**

1. Capacitors

2..Inductors

3. Resistors

4. Voltmeter (0 – 500v), connecting wires, A.C. source, break and make switch.

**LEARNING OBJECTIVES **

By the end of the lesson, students should be able to:

SIMPLE A.C. CIRCUITS

PERFORMANCE OBJECTIVE

Students should be able to:

1. explain the peak and v.m.s. values of current and p.d.

2. establish the phase relationship between current and p.d in an a.c. circuit.

3. explain reactance and impedance.

4. determine current in circuits containing:

- resistance and capacitance.

- resistance, inductance and capacitance.
5. determine power in an a.c. circuit.

**CONTENTS OF THE LESSON**

**FOCUS LESSONS **

1. Alternating current circuits:

- nomenclature in a.c. circuits

- peak and r.m.s. values

- series circuits containing resistance, inductance, and capacitance

- reactance and impedance.
2. Power in an a.c. circuit.

**LESSON PRESENTATION**

TEACHER’S ACTIVITIESThe teacher use vectors to show the directions of resistance, inductance and capacitance in an a.c. circuit.

STUDENT’S ACTIVITIESThe students calculate current in a simple a.c. circuit.

**LESSON EVALUATION**

Students to solve simple problems on peak value, r.m.s value, resistance, inductance, reactance and impedance.

**THEME – FIELDS AT REST AND IN MOTION**

**TOPIC 2 – ELECTRIC FIELD**

**INSTRUCTIONAL MATERIALS**

1. Copper/cordon plates

2. Iron plate

3. Suitable electrolyte(s)

4. Connecting wires

5. Centre-zero galvanometer

6. Standard resistors

7. Resistance wires

8. whetstone bridge or meter bridge

9. Potentiometer

10. Cells/accumulators

11. Electrolysis apparatus

12. Discharge tube/oscilloscopes

13. Plug keys

14. Capacitors

**LEARNING OBJECTIVES **

By the end of the lesson, students should be able to:

1. identify all the component parts of simple cell and accumulator.

2. solve problems involving series and parallel connections of resistors and cells.

3. convert galvanometer to an ammeter and to a voltmeter.

4. state the actors on which the resistance of a uniform wire depends.

5. state and demonstrate the condition for a balanced wheatstone bridge circuit and deduce the condition for balance metre bridge circuit.

6. explain the basic principle of the potentiometer circuit.

7. explain the conditions under which liquids and gases conduct electricity.

8. explain the behaviour of charges or charge carriers in liquids and gases in the electric field.

9. describe an application each on electrical conduction through liquids and gases.

10. calculate the electric force between two charges.

11. explain electric field intensity and electric potential.

12. explain the term capacitance.

13. calculate the equivalent capacitance for series and parallel arrangements of capacitors.

14. determine the energy stored in a capacitor.

**CONTENTS OF THE LESSON**

**FOCUS LESSONS **

1. Production of continuum charges – primary cells and secondary cells

2. Electric circuit series and parallel arrangement of cells and resistors

3. Shunt and multiplier

4. Resistivity and conductivity

5. Principle of potentiometer – meter bridge and whetstone bridge

6. Measurement of electric current, potential difference, resistance and e.m.f of a cell

7. Electrical conduction through liquids and gases:

- electrolytes and non electrolytes

- conduction of charged electrolytes

- voltmeter

- electroplating

- hot cathode emission

- applications

8. Faraday’s law of electrolysis

9. Electric force between point charges (Coulomb’s law)

10. Concept of electric field, electric field intensity and electric potential

11. Capacitance – definition, arrangement of capacitors in a circuit and energy stored in a charged capacitor.

**LESSON PRESENTATION**

TEACHER’S ACTIVITIESThe teacher,

1. demonstrates the use of potentiometer, meter bridge and whetstone bridge.

2. leads discussion on the dynamics of charged particles in electrolytes.

3. leads discussion on how the reduction in pressure of a gas in a suitable container leads to electric conduction.

4. leads discussion on how the reduction in pressure of a gas in a suitable container is applied in the florescent tube and cathode ray oscilloscope.

STUDENT’S ACTIVITIESThe students,

1. arrange cells in series and parallel and determine the resultant emf.

2. determine equivalent resistance for resistors arranged in series and parallel.

3. convert a galvanometer to an ammeter and a voltmeter.

4. measure the resistance of a wire by the following methods – ammeter, voltmeter and meter bridge (whetstone bridge circuit).

5. determine the temperature coefficient of resistance for a suitable wire.

6. Use a potentiometer wire to measure emf and compare the values of two emf.

7. set up a potentiometer circuit and calibrate it.

8. Identify solutions that conduct electricity and those that do not

9. determine the current in electrolysis.

10. calculate the electric force between two point charges in free space. Compare this force with the gravitational force between two protons.

11. calculate the electric field intensity and electric potential of simple systems.

12. determine the equivalent. capacitance for series and parallel arrangements of capacitors.

13. calculate the energy stored in a charged capacitor for given values of V, Q, and C.

**LESSON EVALUATION**

Students to,

1. connect simple circuits.

2. read meters

3. solve simple circuit problems.

4. list conditions under which liquids and gases conduct electricity and set up a simple voltmeter circuit.

5. apply Faraday’s law in solving simple problems in electrolysis.

6. do simple calculations on electric force, electric potential, capacitance and energy stored in capacitors and application of principles.

**THEME – FIELDS AT REST AND IN MOTION**

**TOPIC 3 – ELECTROMAGNETIC FIELD**

**INSTRUCTIONAL MATERIALS**

1. Solenoid

2. Bar magnet

3. Soft iron

4. DC source

5. Galvanometer

6. Plug key

7. Connecting wires

8. Induction

9. Model transformer

**LEARNING OBJECTIVES **

By the end of the lesson, students should be able to:

1. identify the directions of current, magnetic field.

2. explain the action of a loop wire carrying current in a magnetic field.

3. explain the basic working principle of the galvanometer and the electric motor.

4. state and explain Faraday’s law of electromagnetic induction

5. state and explain the implications of Lenz’s law

6. explain how the conversation principle is involved in both laws with regards to charge and energy.

7. explain the principle underlying the production of direct and alternating current

8. state the use of induction coils and transformers

9. explain why the cores of the induction coil and the transformers are laminated

**CONTENTS OF THE LESSON**

**FOCUS LESSONS **

1. Concept of electromagnetic field

- interaction between magnetic field and currents

- a current carrying wire in a magnetic field
2. A current carrying solenoid in a magnetic field

3. Applications of electromagnetic field:

- electric motor

- moving coil galvanometer

- induction coil

4. Electromagnetic induction:

- Faraday’s law

- Lenz’s law

- Motor generator effect
5. Eddy currents

**LESSON PRESENTATION**

TEACHER’S ACTIVITIESThe teacher,

1. shows the relationship between the directions of the magnetic field, current and the force by using a current carrying wire in a magnetic field using Fleming’s left hand rule.

2. shows the effect of passing current through two conductors:

- parallel in the same direction

- parallel in the opposite directions

- perpendicular to each other
* at an angle to each other such that 0o<θ<90o.

3. demonstrates the effect of switching the current on and off in a solenoid which is connected to another solenoid to which a galvanometer is connected.

4. demonstrates the motor generator effect

5. demonstrates the principles of induction coil

6. demonstrates the principles of the transformer

7. shows an Eddy current by rotating suspended coil in a magnetic field and a laminated core in a magnetic field.

STUDENT’S ACTIVITIES

The students,

1. investigate the effect of passing current through a solenoid in a magnetic field.

2. investigate the effect of rotating wire in magnetic field.

3. investigate the effect of moving a magnet in a solenoid or coil carrying current near a solenoid.

**LESSON EVALUATION**

Students to,

1. explain application of Faraday’s and Lenz’s law and the conservation principle involved in the laws.

2. list and explain the implications of Lenz’s law.

3. explain the working principle of the electric motor.

4. explain the principles of operation of:

- step up transformer

- step down transformer

- induction coil
5. solve simple problems on conversion of a galvanometer to:

- ammeter

- voltmeter

**THEME – FIELDS AT REST AND IN MOTION**

**TOPIC 4 – MAGNETIC FIELDS**

**INSTRUCTIONAL MATERIALS**

1. Compass needle

2. Iron fillings

3. Bar magnet

4, DC source

5. Soft iron

**LEARNING OBJECTIVES **

By the end of the lesson, students should be able to:

1. plot the magnetic field around:

- a bar magnet

- a straight conductor carrying current

- a solenoid
2. make a magnet from a soft iron bar.

3. make an electro-magnet.

4. describe the working principles of an electric bell and a telephone ear piece.

5. locate the earth’s magnetic north-south direction.

6. explain the magnetic force on a moving charge.

7. state the relation between magnetic force and the motion of a charge in a magnetic field.

**CONTENTS OF THE LESSON**

**FOCUS LESSONS **

1. Concept of magnetic field

2. Magnetic field around:

- a bar magnet

- a straight conductor carrying current

- a solenoid
3. Magnets:

- temporary and permanent

- making magnets
4. application of electro-magnetic field

5. Earth’s magnetic field:

- description and use

- mariner’s compass
6. Magnetic force on a moving charge.

**LESSON PRESENTATION**

TEACHER’S ACTIVITIESThe teacher,

1. demonstrates how to distinguish between magnetic and non magnetic materials.

2. leads discussion on the formula, F= qv ˟ B as an example of a vector product.

STUDENT’S ACTIVITIES

The students,

1. investigate the field around a conductor by using the compass, needle and iron fillings.

2. plot the magnetic field of a bar magnet

3. make magnets by conduct method; electricity.

4. suspend a bar magnet horizontally and locate the earth’s N-S direction.

5. solve simple problems involving motion of a charged particle in a magnetic field.

**LESSON EVALUATION**

Students to,

1. explain the concept of magnetic field.

2. solve simple problems involving the force on a moving charge in a magnetic field

3. plot lines of force of:

- permanent magnet

- current carrying conductor.

**THEME – FIELDS AT REST AND IN MOTION**

**TOPIC 5 – GRAVITATIONAL FIELD**

**INSTRUCTIONAL MATERIALS**

1. Pendulum bob, string, stop watch, metre rule, split cork, stand and clamp

2. Charts, film, etc.

**LEARNING OBJECTIVES **

By the end of the lesson, students should be able to:

1. calculate the gravitational force between two masses.

2. calculate the gravitational force between two planets.

3. explain the meaning of ‘G’ and show that ‘g’ is the force per unit mass on the earth’s surface.

4. relate Kepter’s laws to the motion of the solar system.

5. distinguish between natural and artificial satellite.

6. explain how artificial satellites are launched.

7. explain the concept of escape velocity.

**CONTENTS OF THE LESSON**

**FOCUS LESSONS **

1. Gravitational force between two masses (Newton’s law of universal gravitation)

2. ‘G’ as a universal constant

3. Solar system

4. Kepter’s laws

5. Natural and artificial satellites

6. Escape velocity.

**LESSON PRESENTATION**

TEACHER’S ACTIVITIESThe teacher,

1. explains the movement of the planets in the solar system using a chart.

2. shows films on the launching of satellites.

STUDENT’S ACTIVITIES

The students,

1. calculate the gravitational force between:

- two protons

- a proton and an electron

- two planets
2. Calculate the force per unit mass on the earth’s surface.

**LESSON EVALUATION**

Students to,

1. explain the difference between g and G.

2. solve simple problems on gravitational force between any given two masses.