Electrical Engineering - Alternating Current and Voltage - Discussion
Discussion Forum : Alternating Current and Voltage - General Questions (Q.No. 19)
19.
Sine wave A has a positive-going zero crossing at 45°. Sine wave B has a positive-going zero crossing at 60°. Which of the following statements is true?
Discussion:
24 comments Page 1 of 3.
Eoj said:
2 years ago
Get the power factor of both waves.
Wave A = 45 degrees.
Wave B = 60 degrees.
P.F. (Wave A) = cos (45) = 0.707.
P.F (Wave B) = cos (60) = 0.5.
The implication of this is that Wave A is already at the peak, while Wave B is about the get the peak. Thus, Wave A is leading Wave B by 15 degrees.
Wave A = 45 degrees.
Wave B = 60 degrees.
P.F. (Wave A) = cos (45) = 0.707.
P.F (Wave B) = cos (60) = 0.5.
The implication of this is that Wave A is already at the peak, while Wave B is about the get the peak. Thus, Wave A is leading Wave B by 15 degrees.
Abhisek said:
5 years ago
Option A is correct, Consider the Zero Crossing concept, then you will get it.
Shah zeb said:
6 years ago
Answer B is the correct option because wave b is at 60 and the wave is at 45.
Kamran said:
6 years ago
As meter move from left to right. So as respect to this 45 angle will lead to 60 degree angle. A is correct.
Abdul Majid said:
7 years ago
Hi all.
Option B is correct. Here is the explanation:
That signal leads which crosses a point before the other signal.
δ _t=∠/360*f.
Where Δ_t=tB-tA.
And ∠ is phase difference given by:
∠=∠B-∠A.
And it should be cleared here if Δ t is +ve then signal A is lagging and Vice versa
In our problem.
∠=60-45=15=+ve so Δ t is also +ve and hence wave A is lagging wave B by 15 degrees.
I hope this helped you.
Thanks
Option B is correct. Here is the explanation:
That signal leads which crosses a point before the other signal.
δ _t=∠/360*f.
Where Δ_t=tB-tA.
And ∠ is phase difference given by:
∠=∠B-∠A.
And it should be cleared here if Δ t is +ve then signal A is lagging and Vice versa
In our problem.
∠=60-45=15=+ve so Δ t is also +ve and hence wave A is lagging wave B by 15 degrees.
I hope this helped you.
Thanks
Dhaval said:
8 years ago
Answer should be B because lagging and leading does not depend on Cross zero first. It depends upon the angle of the wave. So right answer should be B.
(1)
Waheed ullah khattak said:
9 years ago
B is the correct option.
Akshay said:
9 years ago
Option A is right because A reaches to 0 before B at 15 degrees.
Lovaraju said:
9 years ago
As per my knowledge B is right.
Sunil Malappuram said:
9 years ago
I think wave B leads. Please give clarification about the answer.
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