1. The main purpose of performed open-circuit test on a transformer is to find its
Answer : A. core loss
Explanation:-
2. When compared to a Delta-Delta three phase transformer bank, the capacity of V-V transformer bank is
Answer : A. 57.7%
Explanation:-
3. The equivalent primary resistance of the transformer with k=5 is 0.2ohm. When it is reffered to secondary, then it becomes
Answer : D. 2.5 ohms
Explanation:-
4. In the emf equation of a transformer, the flux involved is
Answer : C. maximum value
Explanation:-
5. An AC current given by i=14.14sin(ωt-π/4) has a rms value of
Answer : B. 10 A
Explanation:-
6. The reactance of a capacitor to alternating current of frequency 50Hz is 10Ω. If the frequency is increased to 100Hz, then its reactance becomes
Answer : A. 5 Ω
Explanation:-
7. The form factor in ac means the ratio of
Answer : D. rms value to peak value
Explanation:-
8. In two wattmeter method of measuring 3-phase power and power factor is 0.5, then one of the wattmeter will read
Answer : B. Zero
Explanation:-
9. A coil of resistance 100Ω and inductance 100μH is connected in series with 100pF capacitor across a 10V variable frequency supply. The resonance frequency of the circuit is ______
Answer : 1.59 x 10^6 Hz
Explanation:-
The resonance frequency of the Series RLC circuit is 1/(2Ï€sqrt(LC))
10. A parallel circuit consists of a 2.5μF capacitor and a coil whose resistance and inductance are 15Ω and 260 mH respectively, the dynamic impedance of the circuit is
Answer : D. 6933 ohms
Explanation:-
Dynamic Impedance = L/CR
= 260x10^(-3)/(2.5x10^(-6)x15)
= 6933.333 ohms
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