Electrical Measurements

  1. Which of the following are the more accurate instrument?
    a. Tangent galvanometer
    b. Potentiometer
    c. Both a & b
    d. Hot wire meter
  2. Which of the following is absolute instrument?
    a. Rayleigh current meter
    b. Pointing meter
    c. Both a & b
    d. Thermo coupled meter
  3. 115ohm is measured in the following 3 ways
    which of the following is true?
    1. 115ohm 2. 115.0ohm 3. 0.115*10^3
      a. 1&3 is same precision , 2 high precision
      b. 1&2 is same precision, 3 high precision
      c. 1,2&3 is same precision
      d. insufficient data
  4. For a (0-30)A ammeter, the input and output readings are shown in below figure. Calculate
    output non-linearity and input linearity in instrument.
    input(amp) 0 5 10 15 20 25 30
    output(amp) 0 6 12 18 21 26 29
  5. a. What is the range and span of the 9(0-300)v voltmeter?
    b. A thermistor measures a temperature of -15degree c and 45 degree c
  6. A (0-200)v voltmeter having 100 division and (1/10) of each division can be estimated the resolution of the voltmeter is?
  7. A pyrometer dead zone is 10% of span of instrument. If the scale of the pyrometer is calibrated as (10deg.c -20deg.c). Calculate the change in input before output is calculated?
  8. In a wheat stone bridge, change of 10ohm in arm resistance causes 2mm deflection in galvanometer, calculate
    1. Sensitivity
    2. Deflection factor