Electronic Measurements and Instrumentation Mid - I, September - 2014

1.Purely mechanical instruments cannot be used for dynamic measurements because they have
  • High Inertia
  • Large time constant
  • Higher Response Time
  • All The Above
Answer: D
2.The Power can be controlled in a Circuit by :
  • Controlling the Voltage applied to load
  • Controlling the current level in the circuit
  • Using pulse modulation of power
  • All the above
Answer: D
3.____________ Bridge used for measument of low resistances
  • Maxwell’s
  • Wheatstone
  • Schering
  • Kelvin
Answer: D
4.The following are the Desirable dynamic characteristics of a management system :
  • Fast response, fidelity, Measuring log & dynamic error
  • Fast response & Measuring log
  • Fidelity & Measuring log
  • Fast response & fidelity
Answer: D
5.The high torque to weight ratio in an analog indicating instrument indicates :
  • High friction loss
  • Low friction loss
  • Nothing as regards friction loss
  • None of the above
Answer: B
6.Thermocouple instruments can be used for a frequency range
  • Up to 100Hz
  • Up to 5000H
  • Up to 1MHz
  • Up to 50Hz above
Answer: D
7.The controlling torque in single phase power factor meter is provided by :
  • Spring control
  • Gravity control
  • Stiffness of suspension
  • None of the above
Answer: D
8.The value of resistance of an earthing electrode depends upon :
  • Shape & material of electrode
  • Depth to which electrode is driven into earth.
  • Specific resistance of soil
  • All the above.
Answer: D
9.A Wheat Stone bridge cannot be used for precision measurements because errors are introduced into an account of
  • Resistance of connections leads
  • Thermo – electric emfs
  • Contact Resistance
  • All the above.
Answer: D
10.Maxwell’s inductance bridge is used for measurements of inductance of
  • Low @ Coils
  • Medium @ Coils
  • High @ Coils
  • Low & medium @ Coils
Answer: B
11.A null type of instrument as compared to a definition type of instrument has____________________
Answer: Higher accuracy
12.A pressure measurement instrument is calibrated between 10 bar & 250 bar. The scale span of instrument is _________________________
Answer: 240 bar
13.An amplifier has input signal voltage of 25mV a noise voltage 2.5mV. The signal to noise ratio is________________
Answer: 100
14.An 0-10A ammeter has a guaranteed accuracy of 1% full scale deflection. The limiting error while reading 2.5A is ____________________
Answer: 4%
15.A 1mA ammeter has a resistance of 100 Ohm it is to be converted to 1A ammeter. The value of short resistance is___________________________
Answer: 0.1001 Ohm
16.The d’ Arronval movement is rated at 50mA. It is sensitivity is ___________________
Answer: 20000 Ohm/V
17.The resistance of earthing electrode should be ___________________ from the point of view of safety.
Answer: Low
18.A potentio Meter is basically a ____________________
Answer: Null type instrument
19.Frequency can be measured by using _____________________
Answer: Wien’s bridge
20.The equations under balance conditions for a bridge are _________________
Answer: R1= R2R3/R4 & L1 = R2R3L4