Question

The main error when measuring low resistances is _________

(a) power dissipation of the arms

(b) voltage drop across the emf source

(c) lead and contact resistance

(d) current flowing through the circuit

The question was asked in a job interview.

I want to ask this question from Measurement Errors in a Wheatstone Bridge in division Measurement of Resistance of Electrical Measurements

Answer 1

Right answer is (c) lead and contact resistance

The explanation is: Voltage drop across the circuit along with power dissipation lead to errors in the measurement of low resistances. The resistance of leads and contacts of the external circuit adds to the values in the circuit. This is the main source of error while measuring low resistances.