Network Elements and the Concept of Circuit
- A voltage has a value of V = 180 cos (t + 12°) and current – i = 2.5 cos (t + 5°) the power factor of the circuit is—
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Power factor = cos (12° – 5º) = cos 7° = 0.993
The power factor is lagging because the current i = 2.5 cos (ωt + 5º) lag to the voltage,
V = 180 cos (ωt + 12º) by 7°.Correct Option: D
Power factor = cos (12° – 5º) = cos 7° = 0.993
The power factor is lagging because the current i = 2.5 cos (ωt + 5º) lag to the voltage,
V = 180 cos (ωt + 12º) by 7°.
- The total impedance of the circuit shown is—
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ZAB = (4 + j8) || (4 – j8) + 10
= (4 + j8) (4 – j8) + 10 4 + j8 + 4 – j8 = 16 + j32 – j32 – j2 64 + 10 8 = 16 + 64 + 10 = 80 + 10 8 8
= 20 ΩCorrect Option: A
ZAB = (4 + j8) || (4 – j8) + 10
= (4 + j8) (4 – j8) + 10 4 + j8 + 4 – j8 = 16 + j32 – j32 – j2 64 + 10 8 = 16 + 64 + 10 = 80 + 10 8 8
= 20 Ω
- In fig. (a) the values i L, Vc as shown have initial values i L (0—) = 1 and Vc (0—) = 2 fig. (b) is the equivalent circuit in the s-domain. The values of V1 and V2 are—
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Since given iL (0–) = i L (0+) = 1
VL = L i L (0+) = 2 × 1 = 2and Vc (0–) = 2 s V2 = 2V s Correct Option: B
Since given iL (0–) = i L (0+) = 1
VL = L i L (0+) = 2 × 1 = 2and Vc (0–) = 2 s V2 = 2V s
- The dimension of LC is—
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We know that
Frequency = 1 2π√LC 1 = 1 T 2π√LC
LC = (time)2
or the dimension of LC = (second)2Correct Option: D
We know that
Frequency = 1 2π√LC 1 = 1 T 2π√LC
LC = (time)2
or the dimension of LC = (second)2
- A source Vs = 200 cos t delivers power to a load at power factor 0.8 lagging. The reactive power is 300 VAR. The Pav is given by—
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NA
Correct Option: C
NA
