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One single phase wattmeter operating on 230V and 5A for 5 hours makes 1940 revolutions. Meter constant in revolutions is 400. What is the power factor of the land?

A. 1

B. 0.84

C. 0.73

D. 0.65

Answer: Option B

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Comments ( 7 )

  1. Arun Singh
    Arun Singh :
    12 months ago

    kWh consumed=230 x 5 x 5 =5.750 kWh
    meter constant= 400 rev/kWh
    rev for 5 hours = 1940
    kWh= rev/ meter constant= rev/rev/kWh =1940/400=4.85 kWh
    Actual power factor=4.85/5.75=0.843

  2. Sreemadhur Lokarapu
    Sreemadhur Lokarapu :
    1 year ago

    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

  3. Sanjay Kumar
    Sanjay Kumar :
    1 year ago

    Aparrent power (kvah)= 230×5x5/1000=5.750
    Active power (KWh)= 1940/400=4.85
    P.f (Cos €) =KWh/Kvah= 4.85/5.75=0.843

  4. Smitha Saji
    Smitha Saji :
    1 year ago

    kWh consumed=230 x 5 x 5 =5.750 kWh
    meter constant= 400 rev/kWh
    rev for 5 hours = 1940
    kWh= rev/ meter constant= rev/rev/kWh =1940/400=4.85 kWh
    Actual power factor=4.85/5.75=0.843

  5. Chaitanya
    Chaitanya :
    2 years ago

    GIVEN V=230V, I=5A& T=5 Hours
    meter constant =400, revolution=1940
    energy (E)=REVOLUTION/ METER CONSTANT
    energy (E)=1940/400 =4.85 KWH = 4850WH
    Energy consumed(E) = 230v *5A * 5 hours = 5.750 kwh = 5750 WH
    POWER FACTOR = 4850/5750 =0.843

  6. Shivakumararm Shivakumararm
    Shivakumararm Shivakumararm :
    3 years ago

    Energy consumed = 230v *5A * 5 hours = 5.750 kwh
    Revolution constant =400/kwh so =1940/400= 4.85
    P.F = 4.85/5.750= 0.84
    @hari

  7. Harichandana Bhumireddy
    Harichandana Bhumireddy :
    3 years ago

    please explain this question sir.

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