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For the circuit shown below, if the power dissipated in the 6Ω resistor is zero then V is—
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- 20√2 ∠ 45°
- 20 ∠ 30°
- 20 ∠ 45°
- 20√2 ∠ 30°
- 20√2 ∠ 45°
Correct Option: C
The given circuit:
Given that power dissipated in the 6Ω resistor is zero, it means voltage at node 1 is same as 2 (i.e., V1 = V2)
KCL at node 1
+ | + | = 0 | |||
1 | j1 | 6 + j8 |
or
V1 1 + | 20 0°(since V1 = V2) | |
j1 |
or
V1 = 20 0° | .........…(i) | |
(j + 1) |
Again KCL at node 2:
+ | V1 | + | = 0 | ||
6 + j8 | 5 | 5 |
or
= | V | (since V1 = V2) | |
5 | 5 |
or
V2 = | ...........(ii) | |
2 |
From equation (i) and (ii)
20 0° | = | ||
j + 1 | 2 |
or
V = | |
2 × 45° |
20 2 45°
Hence alternative (A) is the correct choice.