Electrical Measurements Practice Test 2

1. What is earthing?

connecting electrical machines to earth

connecting the electrical machines to source

providing a connection to the ground

providing a source of current

2. What is the significance of Anderson bridge with respect to Q factor?

easy to balance the bridge

no balance can be done

intermediate balance can be achieved

difficult to balance the bridge

3. Angular balance equation is given by which of the following relation?

θ₂ + θ₄ = θ₁ + θ₃

θ₂ × θ₄ = θ₁ × θ₃

θ₁ × θ₄ = θ₂ × θ₃

θ₁ + θ₄ = θ₂ + θ₃

4. Earthing does not help in protecting the equipment.

False

True

5. Impedance Z₄ consists of _________

combination of capacitance Cx and resistance Rx

resistance R_x

capacitance C_x

consists of a detector

6. For inductive impedances, the phase angle is _______

negative

exponential

positive

zero

7. A resistance R is measured using the connection shown in the below figure.

The current measured is 10 A on ranges 100A and the voltage measured is 125 V on 150 V range. The scales of the ammeter and voltmeter are uniform. The total number of scale divisions of the ammeter is 100 and that of the voltmeter is 150. The scale division can be distinguished. The constructional error of the ammeter is ± 0.3% and that of voltmeter±0.4%. The resistance of the ammeter is 0.25 Ω.
The possible error in the measurement of R is?

±0.625 Ω

±0.15 Ω

±0.11 Ω

±0.867 Ω

8. R_a and R_d are the opposite arms of a Wheatstone bridge as are R_c and R_b. The source voltage is applied across R_a and R_c. Then when the bridge is balanced which one of the following is true?

R_a = R_b Rd/R_c

R_a = R_b R_c/R_d

R_a = R_c R_d/R_b

R_a = R_b + R_c + R_d

9. In the simplest form, an AC bridge consists of ____________

source and detector

arms and source

arms, source and a detector

arms and detector

10. Resistance is measured by the voltmeter-ammeter method employing DC excitation and a voltmeter is connected directly across the unknown resistance. If the voltmeter and ammeter readings are subject to maximum possible errors of ±2.4 % and ±1% respectively, then the magnitude of the maximum possible percentage error in the value of resistance deduced from the measurement is?

1.4 %

2.4 %

3.4 %

1.7 %