71. Thermocouples are
    

1. 1. passive transducers

   
   
   

   2. active transducers

   
   
   

   3. both (a) and (b)

   
   
   

   4. output transducers

   
   
   

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   NA

   Correct Option: B

   NA

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72. Three types of temperature transducers are compared as regards their sensitivity. The order in which they exhibit their sensitivities (highest to lowest) is

1. 1. thermistors, RTDs, thermocouples

   
   
   

   2. thermocouples, RTDs, thermistors

   
   
   

   3. RTDs, thermistors, thermocouples

   
   
   

   4. RTDs, thermocouples, thermistors

   
   
   

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   NA

   Correct Option: A

   NA

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73. The temperature transducers exhibit no– linear behaviour. The order in which they exhibit no linearity (highest to lowest) is

1. 1. thermocouples, RTD, thermistors

   
   
   

   2. thermistors, thermocouples, RTDs

   
   
   

   3. RTDs, thermocouples, thermistors

   
   
   

   4. Thermistors, RTDs, thermocouples

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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74. Some wire-wound resistors have bifilar winding. This type of winding is used to

1. 1. increase the thermal stability

   
   
   

   2. reduce the tolerance

   
   
   

   3. reduce the inductance of winding

   
   
   

   4. double the power rating of the resistance

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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75. A metal strain gauge factor of two. Its nominal resistance is 120 ohms. If it undergoes a strain of 10^–5, the value of change of resistance in response to the strain is

1. 1. 240 ohms

   
   
   

   2. 2 × 10⁵ohm

   
   
   

   3. 2.4 × 10^–3 ohm

   
   
   

   4. 1.2 × 10^–3 ohm

   
   
   

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1. View Hint View Answer Discuss in Forum

   Gauge factor =	dR/R
   	ξa

   
   

   ∴	dR	= 2 × 10-5
   	R

   
   or dR = 2 × 120 × 10^–5 = 2.4 × 10^–3

   Correct Option: C

   Gauge factor =	dR/R
   	ξa

   
   

   ∴	dR	= 2 × 10-5
   	R

   
   or dR = 2 × 120 × 10^–5 = 2.4 × 10^–3

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