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
- (A) 0.8 leading power factor
- (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