1. A 1000 ohms/V meter is used to measure a resistance on 150 V scale. The meter resistance is ________kΩ

1. 1. 6

   
   
   

   2. 52

   
   
   

   3. 6.67

   
   
   

   4. 8.7

   
   
   

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1. View Hint View Answer Discuss in Forum

   Resistance = Sensitivity at ohm × Voltage in volts
   

   =	1000	= 6.67 ohms
   	150

   Correct Option: C

   Resistance = Sensitivity at ohm × Voltage in volts
   

   =	1000	= 6.67 ohms
   	150

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2. A 0-10 mA PMMC ammeter reads 4 mA in a circuit. I ts bottom control spring snaps suddenly. The meter will now read nearly ____________mA

1. 1. 0

   
   
   

   2. 2

   
   
   

   3. 1

   
   
   

   4. 3

   
   
   

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1. View Hint View Answer Discuss in Forum

   The spring gives the controlling torque and is connected in series with the coil. If the spring is snapped, there will be no deflection.

   Correct Option: A

   The spring gives the controlling torque and is connected in series with the coil. If the spring is snapped, there will be no deflection.

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3. One single-phase wattmeter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. Meter constant in revolutions is 400. The power factor of the load will be _________

1. 1. 0.8

   
   
   

   2. 0.5

   
   
   

   3. 0.4

   
   
   

   4. 0.9

   
   
   

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1. View Hint View Answer Discuss in Forum

   Energy consumed = 230 × 5 × 5 = 5750 Wh
   = 5.57 kWh Revolution constant = 400 rev/kWh
   

   ∴ kWh =	1940	= 4.8
   	400

   
   

   Power factor =	4.8	= 0.8
   	5.75

   Correct Option: A

   Energy consumed = 230 × 5 × 5 = 5750 Wh
   = 5.57 kWh Revolution constant = 400 rev/kWh
   

   ∴ kWh =	1940	= 4.8
   	400

   
   

   Power factor =	4.8	= 0.8
   	5.75

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4. A resistance strain gauge with a gauge factor of 3 is fastened to a steel member subjected to a stress of 100 N/mm². The modulus of elasticity of steel is approximately 2 × 10⁵ N/mm². The percentage change in resistance is ________

1. 1. 0.15

   
   
   

   2. 15

   
   
   

   3. 2

   
   
   

   4. 55

   
   
   

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1. View Hint View Answer Discuss in Forum

   Gauge factor =	∇R/R
   	ΔL/L

   
   

   But	ΔL	=	100
   	L		2 × 105

   
   

   ∴	ΔR	=	3 × 100
   	R		2 × 105

   
   

   ∴ Percentage change =	∇R	× 100 = 0.15
   	R

   Correct Option: A

   Gauge factor =	∇R/R
   	ΔL/L

   
   

   But	ΔL	=	100
   	L		2 × 105

   
   

   ∴	ΔR	=	3 × 100
   	R		2 × 105

   
   

   ∴ Percentage change =	∇R	× 100 = 0.15
   	R

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5. A certain meter has a sensitivity of 50,000 Ω/V. The current required to deflect the meter movement to full-scale will be ____________µA

1. 1. 25

   
   
   

   2. 20

   
   
   

   3. 24

   
   
   

   4. 11

   
   
   

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1. View Hint View Answer Discuss in Forum

   Current =	Voltage
   	resistance

   
   

   =	1	= 20μA
   	50,000 Ω/V

   Correct Option: B

   Current =	Voltage
   	resistance

   
   

   =	1	= 20μA
   	50,000 Ω/V

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