Arrangement for measurement of Resistance
CONDUCTIVITY OF 0.001M KCL SOLUTION AT 298 K IS 0.146 X 10-3 S CM-
1
. 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