Question 1:
a) Define the terms: Accuracy, Precision, Sensitivity, Resolution and Error
b) Differentiate the difference between accuracy and precision.
Question 2:
a) Explain different types of errors encountered in measuring instruments.
b) A set of independent current measurements was taken by six observers and recorded as 12.8 mA, 12.2 mA, 12.5 mA, 13.1 mA, 12.9 mA and 12.4 mA. Compute arithmetic mean, the deviations from the mean, average deviation, standard deviation, Variance, probable error, 1σ error and 2σ error.
Question 3:
a) What do you mean by the term limiting error? How do you handle this error in compound measurements?
b) Two resistors have the ratings: R1=36Ω±5% and R2=75Ω±5%. Compute the magnitude of error in each resistor, the limiting error in ohms and in percentage when the resistors are joined in series and as well in parallel.
Question 4:
a) Write a brief note on dynamic errors of the measuring instruments.
b) A resistor is measured by the voltmeter-ammeter method. The voltmeter reading is 123.4 V on the 250 V scale and the ammeter reading is 283.5 mA on the 500 mA scale. Both meters are guaranteed to be accurate in ±1% of the full scale reading. Compute the indicated value of the resistor; and the limits in which you can guarantee the result.
Question 5:
a) Describe the principle of PMMC instrument.
b) Draw the schematic comprising values for an Ayrton shunt for a meter movement having a full scale deflection of 1 mA and an internal resistance of 500 Ω to cover the current ranges of 10, 50, 100 and 500 mA.
Question 6:
a) What is loading effect of a voltmeter? How can offset this practically?
b) Design a multi range voltmeter with voltage ranges of 0-10V, 1-50V, 0-250V and 0-500V by using a basic d’Arsonval movement with an internal resistance of 100 Ω and full scale deflection current of 1 mA. Draw the schematic comprising values.