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?

Answer Posted / nageshwaran.n

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



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

please send previous exams question papers

1408


Why is remote backup preferred to local backup?

1504


what is the best method of grounding in 30 MW generator?

1515


What is the complete procedure of erection of electrical panel in industry

1393


I need model question papers for RRB section engineer Chennai... Please send to my E-mail Id:- maitheerainbow@gmail.com

1485






what is the difference between electrical choke and electronic choke?

2100


which types of relay used in acb and vcb?

2326


What is the Difference between Ac Drives and Dc Drives? According to application, speed, Torque, cost, Reliability, Construction, Motor etc... Thankyou !!!

1686


HOW CAN I GET 5CORE HO7 CABLE SIZE IF I HAVE 1800A?

1632


what happens to the water pump if ground water level is slowly decreasing?our water pump is varying from no-load full-load due to this problem

1227


what happens to the supply voltage if there is any change in frequency?

5694


What is the relationship between voltage,current & frequency?

1282


why and how current drawn by battery charger depends upon the altitude where it is located?

1579


How to calculate the heat load for a electrical room

2621


If a current -8+6sin6t is flowing three ammeter, one is a centre zero PMMC meter, one is true rms meter and one is moving iron meter. What are the reading of these three meter respectively?

1652