161. Which one of the following methods is used to measure power output of a radio transmitter while it is radiating?

1. 1. Electrostatic meter

   
   
   

   2. Three-wattmeter method

   
   
   

   3. Three-ammeter method

   
   
   

   4. Two-wattmeter method

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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162. The sensitivity of thermostats as compared with sensitivity of platinum resistance temperature detector over a temperature range of– 100° to 400°C to change in temperature is

1. 1. 100 times

   
   
   

   2. 10_{6 times}

   
   
   

   3. 10⁷ times

   
   
   

   4. 10³ times

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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163. Rectifier moving coil instruments respond to

1. 1. peak value, irrespective of the nature of the wave form

   
   
   

   2. average value for all wave forms

   
   
   

   3. rms value for all wave forms

   
   
   

   4. rms value for symmetrical square wave form

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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164. Ratio of the readings of two watt meters connected to measure power in a balanced 3-phase load is 5: 3 and the load is inductive. The power factor at load is

1. 1. 0.917 lead

   
   
   

   2. 0.917 lag

   
   
   

   3. 0.6 lead

   
   
   

   4. 0.6 lag

   
   
   

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1. View Hint View Answer Discuss in Forum

   tan φ = √3	W1 - W2	= √3	5 - 3	=	√3
   	W1 + W2		5 + 3		4

   
   

   ∴ cos φ =	1	= 0.917 (lag)
   	√19

   Correct Option: D

   tan φ = √3	W1 - W2	= √3	5 - 3	=	√3
   	W1 + W2		5 + 3		4

   
   

   ∴ cos φ =	1	= 0.917 (lag)
   	√19

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165. If the practical units of voltage and current wave each made 20 times as large as they are at present, what would be the consequent alteration in the size of the unit of capacitance?

1. 1. 200 times

   
   
   

   2. 60 times

   
   
   

   3. 20 times

   
   
   

   4. Nil

   
   
   

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1. View Hint View Answer Discuss in Forum

   Capacitance,C =	Charge, Q	=	It
   	Voltage, V		V

   
   Since I and V units are both charged by the same fact or and time unit is not changed, hence capacitance unit is not affected.

   Correct Option: B

   Capacitance,C =	Charge, Q	=	It
   	Voltage, V		V

   
   Since I and V units are both charged by the same fact or and time unit is not changed, hence capacitance unit is not affected.

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