Instrument Transformers MCQ - Set 06 - ObjectiveBooks

# Practice Test: Question Set - 06

1. The transformer oil should have _______ volatility and _______ viscosity.
(A) Low, low
(B) High, high
(C) Low, high
(D) High, low

2. If 25 W of power are applied to the primary of an ideal transformer with a turns ratio of 10, the power delivered to the secondary load is
(A) 25 W
(B) 0 W
(C) 250 W
(D) 2.5 W

3. For given applied voltage, with the increase in frequency of the applied voltage
(A) Eddy current loss will decrease
(B) Eddy current loss will increase
(C) Eddy current loss will remain unchanged
(D) None of the above

4. An autotransformer is one in which the primary and secondary are automatically coupled.
(A) True
(B) False

5. The primary of a transformer is connected to a 6 V battery. The turns ratio is 1 : 3 and the secondary load, RL, is 100 Ω. The voltage across the load is
(A) 0 V
(B) 6 V
(C) 18 V
(D) 2 V

6. For a transformer, operating at constant load current, maximum efficiency will occur at
(B) 0.8 lagging power factor
(C) Zero power factor
(D) Unity power factor

7. If a transformer is continuously operated the maximum temperature rise will occur in
(A) Core
(B) Windings
(C) Tank
(D) Any of the above

8. If a transformer has 50 turns in the primary winding and 10 turns in the secondary winding, what is the reflective resistance if the secondary load resistance is 250 Ω?
(A) 250 Ω
(B) 25 Ω
(C) 6,250 Ω
(D) 62,500 Ω

9. A transformer responds only to dc.
(A) True
(B) False

10. Part of the transformer which is most subject to damage from overheating is
(A) Iron core
(B) Copper winding
(C) Winding insulation
(D) Frame or case

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