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 & Solution

Correct Answer: Option B

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8 Comments

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Omkar Jadhav 5 years ago

@Smiths saji thank for your explanation

Arun Singh 6 years 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

Sreemadhur Lokarapu 6 years 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

Sanjay Kumar 6 years 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

Smitha Saji 6 years 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

Chaitanya 7 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

Shivakumararm Shivakumararm 8 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

Harichandana Bhumireddy 8 years ago

please explain this question sir.

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One single phase wattmeter operating on 230V and 5A for 5...

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?

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