power is the product of voltage and current.so we can
measure the value of power just by using ammeter and
voltmeter.......then why do we use a wattmeter?

Answers were Sorted based on User's Feedback

power is the product of voltage and current.so we can measure the value of power just by using amm..

apperent power = voltage X current,
we can calculate apperent power by ammeter and voltmeter
real power = voltage X current X power factor

to measure real power we need wattmeter

 Is This Answer Correct ? 24 Yes 1 No

power is the product of voltage and current.so we can measure the value of power just by using amm..

No doubt, we could use Voltmeter & Ammeter for calculating
Power but only Apparent Power that too at that instant.
Apparent power = voltage X current,

Actual RMS Power (real power) = voltage X current X power
factor

And to measure real power we need Wattmeter only.

 Is This Answer Correct ? 11 Yes 0 No

power is the product of voltage and current.so we can measure the value of power just by using amm..

RIGHT POWER IS VOLTAGE X CURRENT BUT FROM THIS WE GET ONLY
APPERENT POWER,AND WE REQIRE REAL POWER I.E VOLTAGE X
CURRENT X POWE3R FACTOR AND FOR THAT WE REQUIRE WATTMETER

 Is This Answer Correct ? 6 Yes 0 No

power is the product of voltage and current.so we can measure the value of power just by using amm..

Yes as all have already said you dont need to use a watt meter
only if the circuit uses a Direct Current voltage and you can
calculate the power mentally by just looking at the voltmeter and ammeter.

 Is This Answer Correct ? 1 Yes 0 No

power is the product of voltage and current.so we can measure the value of power just by using amm..

if we use more no of meters error is more

 Is This Answer Correct ? 0 Yes 0 No

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