LAB

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LAB 22

• ELECTRICAL RESISTANCE Resistivity (r)

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RESISTANCE
R vs LENGTH ( l )
R a l
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RESISTANCE
R vs X-SECTION AREA (A)
A
A
R a 1/A
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RESISTANCE
R a l
R a 1/A
RA/l CONSTANT r
r RESISTIVITY
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RESISTANCE
R r l / A
r RESISTIVITY
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RESISTIVITY
r R A / l
r W m
Units?
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RESISTIVITY VALUES _at_20 oC
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GOALS

• TO TEST WHAT FACTORS DETERMINE THE RESISTANCE OF
  A CONDUCTOR
• TO DETERMINE THE RESISTIVITY OF NiCr WIRE

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LAB 22 PART 1
R vs LENGTH ( l )
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PROCEDURE PART 1

• PART A R vs L
• MEASURE THE RESISTANCE OF DIFFERENT LENGTHS OF
  NiCr WIRE USING AN OHM METER.
• DEVELOP A DATA TABLE TO RECORD YOUR VALUES.
• HAVE A MINIMUM OF 20 TRIALS

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GRAPH 1 R vs l
RESISTANCE (W)
LENGTH (m)
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LAB 22 PART 2
R vs X-SECTION AREA (A)
A
A
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PROCEDURE PART 2

• PART A R vs A
• MEASURE THE RESISTANCE OF VARYING NUMBER OF
  STRANDS OF NiCr WIRE USING AN OHM METER.
• DETERMINE THE X-SECTIONAL AREA OF EACH TRIAL.
• DEVELOP A DATA TABLE TO RECORD YOUR VALUES.
• HAVE A MINIMUM OF 5 TRIALS

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GRAPH 2 R vs AREA
RESISTANCE (W)
X-SECTIONAL AREA (m2)
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GRAPH 3 R vs 1/AREA
RESISTANCE (W)
INVERSE OF X-SECTIONAL AREA (1/m2)
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WRITE-UP

• DATA TABLES
• GRAPHS
• TRENDLINES
• GRAPH ANALYSIS
• RESISTIVITY CALCULATIONS
• SCREEN SHOT OF Google Search
• CONCLUSION