50. Automatic cold junction compensation in thermocouple is provided by :
A.Connecting thermocouple wires, in opposition
B.A nickel wire resistance in series with a manganin resistance
C.Maintaining cold junction temperature constant by a cooling unit
D.Using a photovoltaic cell

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51. The material used for resistance temperature sensor is :
A.Copper
B.Nickel
C.Platinum
D.Any one of above

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52. To prevent self-heating errors becoming too great, the current through platinum element (100 ohm) is kept at a very small value :
A.0.1 mA
B.1 mA
C.5 mA
D.20 mA

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53. In calibration of temperature sensors by fixed point method, the device is calibrated at :
A.Ice point (0?C)
B.Steam point (100?C)
C.Sulphur point (444.6?C)
D.All of the above

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54. Pick up correct statement about calibration of temperature sensors by comparison method using liquid bath :
A.Water is used for temperatures from 0 to 100?C
B.Special grade of paraffin oil is used for temperatures between 100 and 200?C
C.For temperature between 200 and 600?C, a mixture of sodium nitrate and potassium nitrate is used
D.All of above are true

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55. Local velocity is measured by a:
A.Pitot tube
B.Venturi tube
C.Orifice plate
D.(a) vena contracta device

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56. Flange taps in case of orifice plate are installed:
A.25 mm from each side of the orfice plate
B.D (pipe diameter) upstream and D/2 downstream
C.Just at surface of orifice plate
D.2.5 D upstream and 8 D downstream

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