Transformer mcq objective questions and answers part1

Q1. The transformer laminations are insulated from each other by
(A) paper
(B) thin coat of varnish
(C) mica strip
(D) None of these

Q2. A transformer cannot raise or lower the voltage of a DC supply because
(A) there is no need to change the DC voltage
(B) a DC circuit conversion has more losses
(C) the rate of change of flux is zero
(D) None of these

Q3. An ideal transformer will have maximum efficiency at a load such that
(A) copper loss less than iron loss
(B) copper loss is equal to iron loss
(C) copper loss greater iron loss
(D) None of these

Q4. Two transformers operating in parallel will share the load depending upon their
(A) efficiencies
(B) per unit impedance
(C) leakage reactance
(D) ratings

Q5. The chemical used in breather is
(A) silica gel
(B) asbestos fiber
(C) silica sand
(D) sodium chloride

Q6. The purpose of lamination of transformer core is:
(A) reduce eddy current losses
(B) reduce hysteresis loss
(C) reduce copper losses
(D) All of these

Q7. The noise resulting from vibrations of laminations set by magnetic forces, is termed as
(A) magnetostrication
(B) hum
(C) boo
(D) None of these

Q8. Losses which occur in rotating electric machines and do not occur in transformers are?
(A) copper losses
(B) magnetic losses
(C) friction and windage losses
(D) eddy current losses

Q9. In the transformer which of the following winding has got more cross-sectional area
(A) High voltage winding
(B) Low voltage winding
(C) Primary winding
(D) Secondary winding

Q10. Power transformers are designed to have maximum efficiency at
(A) 80% full load
(B) 60% full load
(C) nearly full load
(D) no load

Q11. The transformer ratings are usually expressed in terms of
(A) amperes
(B) kVA
(C) volts
(D) kW

Q12. In a transformer the energy is transferred from primary to secondary
(A) through air
(B) by the flux
(C) through cooling coil
(D) None of these

Q13. Short circuit test on transformers is conducted to determine:
(A) core losses
(B) copper losses
(C) hysteresis losses
(D) eddy current losses

Q14. Which of the following windings in a transformer has more number of turns?
(A) High voltage winding
(B) Low voltage winding
(C) Primary winding
(D) Secondary winding

Q15. Open circuit test on transformers is conducted to determine:
(A) core losses
(B) copper losses
(C) hysteresis losses
(D) eddy current losses

Q16. Primary winding of a transformer
(A) is always a high voltage winding
(B) can either be a low voltage or high voltage winding
(C) is always a low voltage winding
(D) None of these

Q17. No-load current of a transformer has
(A) has small magnitude and high power factor
(B) has small magnitude and low power factor
(C) has high magnitude and high power factor
(D) has high magnitude and low power factor

Q18. In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are
(A) copper losses
(B) friction and windage losses
(C) hysteresis and eddy current losses
(D) None of these

Q19. Spacers are provided between adjacent coils
(A) to insulate the coils from each other
(B) to provide free passage to the cooling oil
(C) both of these
(D) None of these

Q20. Which of the following factors does not change in a transformer?
(A) Current
(B) Frequency
(C) Voltage
(D) All of the above