Home / ECE / Measurements and Instrumentation :: Section 4

ECE :: Measurements and Instrumentation

  1. As per BIS, the number of accuracy classes of instrument is

  2. A.
    5
    B.
    6
    C.
    7
    D.
    8

  3. In most of instruments, the controlling torque is provided by

  4. A.
    fluid fraction
    B.
    spring
    C.
    eddy current
    D.
    either (a) or (c)

  5. A 0-200 V voltmeter has a sensitivity of 1 kΩ per volt. The resistance of voltmeter is

  6. A.
    1 kΩ
    B.
    200 kΩ
    C.
    100 kΩ
    D.
    50 kΩ

  7. DC ampere hour meter is an indicating instrument.

  8. A.
    True
    B.
    False

  9. The accuracy of measurement by ohmmeter is very good.

  10. A.
    True
    B.
    False

  11. Hay's bridge is suitable for inductances having low L/R ratio.

  12. A.
    True
    B.
    False

  13. Moving iron instrument can be used for ac only.

  14. A.
    True
    B.
    False

  15. In electronic voltmeters the measuring device is a

  16. A.
    moving coil instrument
    B.
    moving iron instrument
    C.
    dynamometer instrument
    D.
    none of the above

  17. An ammeter has a resistance of 50 ohms and a shunt of 0.01 Ω. The deflection is θ. If the shunt resistance is increased to 0.02 Ω, the deflection will be.

  18. A.
    θ
    B.
    C.
    0.5θ
    D.
    0.25θ

  19. The ac bridge in figure is balanced. Z1 = 100∠30°, Z2 = 150∠0°, Z3 = 250∠ - 40° Then Z4 =

  20. A.
    375∠70° Ω
    B.
    375∠ - 70° Ω
    C.
    150∠0° Ω
    D.
    150∠20° Ω