Arrangement for measurement of Resistance
CONDUCTIVITY OF 0.001M KCL SOLUTION AT 298 K IS 0.146 X 10 -3 S CM -
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. SOLUTION : Conductivity , k = 0.146 × 10 - 3 S cm - 1 Resistance , R = 1500 Ω Cell constant = k × R = 0.146 × 10 - 3 × 1500 = 0.219 cm - 1
Arrangement for measurement of Resistance
o The arrangement consists of two resistances R3 and R4 .
o There is a variable resistance R1 and a conductivity cell with unknown resistance R2 . o o The Wheatstone bridge is provided with an oscillator O that acts as source of a . c . power .
o
P .
The arrangement has a suitable detector
The Wheatstone bridge is balanced when there is no flow of current through the detector .
Unknown resistance = R2 = R1R4 / R3 o
o
After calculating the resistance the conductivity can be easily calculated using the formula :
κ = G ' / R