# Lesson Notes By Weeks and Term - Senior Secondary 1

Electric circuit

Term: 2nd Term

Week: 5

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject:      Physics

Topic:-       Electric circuit

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explain the meaning of electric circuit
2. Discuss the ways by which electric current can be produced

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

 PRESENTATION TEACHER’S ACTIVITY STUDENT’S ACTIVITY STEP 1 INTRODUCTION The teacher reviews the previous lesson on electric charges Students pay attention STEP 2 EXPLANATION He explains the meaning of electric circuit Students pay attention and participates STEP 3 DEMONSTRATION He discusses ways in which electric current can be produced Students pay attention and participate STEP 4 NOTE TAKING The teacher writes a summarized note on the board The students copy the note in their books

NOTE

ELECTRIC CIRCUIT

ELECTRIC CIRCUIT

An electric circuit is the path provided for the flow of electric current. The circuit consist of the source of electric energy (e.g. a battery) connected through a conductor (e.g. a wire) to a load (e.g. an electric bulb) and a key or a switch

PRODUCTION OF ELECTRIC CURRENT

Electric Current can be generated from

1. Chemical Energy
2. Heat Energy
3. Mechanical Energy
4. Solar Energy

(a) ELECTRICITY FROM CHEMICAL ENERGY

Electricity is produced from Chemical Energy through the use of electric cell. An electric cell is a device for converting chemical into electric energy. Examples of an electric cell are Voltaic (simple) cell, Daniel cell, Leclanche cell, Accumulator etc.

DEFECTS OF SIMPLY CELLS

Simple cell supplies current only for a short time. This occurs from the following chemical processes

1. Polarization
2. Local Action

i.) Polarization: This is the formation of hydrogen bubbles around the copper plate of the simple cell. It can be reduced by the addition of suitable chemical known as depolarizerg. potassium dichromate.

ii.) Local action: This is the formation of impurities on the zinc plate. The impurities (Iron & Carbon) set up tiny cells around the zinc surface. Local action can be prevented by the process of amalgamation that is rubbing of mercury over the surface of zinc plate.

(b) ELECTRICITY FROM HEAT ENERGY

Solder two different metallic wires (e.g. copper & Iron) to produce bi copper–iron junction. Connect the free end of the wire to a galvanometer. Dip one end of the bi copper–iron junction in boiling water while the other end is connected to the galvanometer known as the cold junction. The essence of connecting galvanometer is to detect current flowing.

(c) ELECTRICITY FROM MECHANICAL ENERGY

The process involved in the production of electric current from a dynamo which illustrates the conversion of mechanical Energy to Electrical Energy. The dynamo operates on the principle of electromagnetic induction.

(d) ELECTRICITY FROM SOLAR ENERGY

This work based on the principle of photo-voltaic cell which provides a simple conversion of electrical energy to solar energy.

EVALUATION:   1. Define electric circuit

1. State and explain the four ways in which electric current can be produced

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively