Design and Construction of a Metre Bridge
CHAPTER ONE
OBJECTIVE OF THE STUDY
This is to help, to increase the apparatus (metre bridge) in physics laboratory in Institute of Management and Technology (IMT), Enugu.
CHAPTER TWO
LITERATURE REVIEW
CONSTRUCTION OF THE METRE BRIDGE
Construction was carried out in accordance with the design and constructions. Some basic tools were used in the construction of the component of the instrument.
OPERATION FOR CONSTRUCTION OF BASE BOARD
A plywood board of mahogany was used. This plywood was saved by means of the handsaw and the two faces edges plained to with using the jack plane. It was cut to the required length by the panel saw. The two faces sides were glass-papered by hand.
The growth in the board for the metre rule was made by hand using the plough plane and the two ends dispelled to form the correct rectangular shape.
The leveling stand was built through the same processes applied for the bare board. Holes for the screws were drilled on a doting machine before they were finally screwed to the baseboard with the aid of a screwdriver. Scotto D. W. 1977.
CHAPTER THREE
MATERIALS AND METHODOLOGY
DESIGN OF THE METRE BRIDGE
Figure III below describes the design of the metre bridge. This is the isometric view of the instrument that is the first elevation side view. The dimensions are all in centimeters.
SPECIFICATIONS
- The materials used are as follows:
- Wooden board
- Leveling stand
- Long and short metal strips
- Copper terminals
- Screws
- Close up strips
- Holder for the wire
- Metre rule
- Copper wire
The designed work is specially called metre bridge (slide wire). The dimensions of all the component parts are listed above. Though the design is not drawn to scale, but it is still to dimension. If this is draw to scale it would pose a problem of not identifying some of the component clearly.
WOODEN BOARD
Length = 120cm
Width = 18cm
Thickness = 2cm
MATERIAL
Mahogany wood.
Two wooden base of 17.0cm by 4.5cm by 2.5cm.
This is located on the both ends of the board metal strips.
CHAPTER FOUR
CALIBRATION OF CONSTRUCTED BRIDGE
DISCUSSION OF ACCURATE CONSTRUCTED METRE BRIDGE
The constructed metre bridge was discussed first of all by connecting the circuit as it shown below and touching the jockey (galvonometer key) on both end terminals, a and b.
There was deflection on both sides of the galvanometer and the circuit connections were then considered to be all right. Then two resistors of equal resistance (20hms) were connected across the grips on both arms of the bridge. The balance point (when the galvanometer pointer should no deflectional was soon the metre rule showing that the instrument measured accurately.
CHAPTER FIVE
FINDINGS, RECOMMENDATIONS AND CONCLUSION
FINDING
Base on the research, it was discovered that a metre bridge is associated with electricity and the study of electricity is an important aspect of physics because it plays a key role in the modern world. The working of most modern appliances such as radio, television, computers and calculators, refrigerators, air conditions, sound systems and electric fans is possible as a result of electricity.
RECOMMENDATION
Since the metre bridge is an instrument used to determine the value of an unknown resistance. One needs to have the knowledge of circuit board and work with a variety of circuits, which include voltage, dividers and the wheatstone bridge. There are three basic quantities, which must be clearly understood before one can proceed with the subject of electricity. These are electric current, potential differences and electric resistances.
CONCLUSION
In the course of the construction of the bridge some difficulties were encountered in the collection of materials because most of the recommended materials were nowhere to be seen in the local markets and scientific shops. Financial constraints posed on serious handicap too.
Different materials were used in the construction of both the standard and the constructed metre bridge. Where as copper metal strips were used in the constructed bridge. A 24 S.W.G. gauge by constantan wire with a diameter of 0.056cm was used as the bridge wire for the constructed bridge. The use of different materials of constantan wires with different thickness in the construction of the bridge does not affect the quality or performance of the constructed bridge is buttressed by the fact that there is a direct correlation between the values obtained from the constructed bridge and those from the standard bridge. In the light of the above argument it follows that copper can be used interchangeable with copper as metal strips in the construction of metre bridge.
REFERENCE
- BESANCON, M. R. (1974): The Encyclopaedia of Physics. Second Edition; Litton Educational Publishing Inc. page 50 – 52.
- BLEANEYB (1965): Electricity and Magnetism. Second Edition; Oxford University Press, London; pg. 205.
- BUECHE, F. J. (1965): Introduction Of Physics Science and Engineers. Second Edition; McGraw, Hill Book Company; pg. 352.
- HALLIDAY, D and RESNICK, R. (1978): Physics Parts I and 2 Combined. Third Edition. John Wiley and Sons Inc. Pg. 23 – 28.
- HUDSON, M. (1973): Structure and Metals. Hutchinsm Educational Ltd., London. Pg. 119 – 200.
- NELKON, M. (1977): Advance Level Physics. Fourth Edition Heinenann Educational Book Ltd. Pg. 43 – 45.
- SCOTTO, D.W. (1973): A Course In Prasctival Physics. Second Edition Cambridge University, London. Pg. 43.
