# Objectives Or Mcqs On Transformer | All Student World

1) Open circuit in a transformer is prefered with
a)    Rated Transformer voltage
b)    Rated transformer current
c)    Direct Current
d)    High frequency supply

2). Open circuit test on transformer gives
a)    eddy current loss
b)    hysteresis loss
c)    copper loss
d)    both 1 and 2

3). In a single phase transformer the magnitude of leakage reactance is the twice the that of resistance of both primary and secondary. With Secondary short circuited, the input power factor is
a)    1/√2
b)    1/√5
c)    2/√5
d)    1/3

4). If Pand P represent core and full load copper loss respectively, the maximum KVA delivered to load corresponding to maximum efficiency is equal to rated KVA is
a)    pi /P
b)    (Pi /P)
c)    √(P/P)
d)    P/P

5). A Transformer has maximum efficiency at 3/4 load. The ratio of iron loss and full load copper loss is
a)    4/3
b)    3/4
c)    9/16
d)    16/9

6). When a short circuit test on a transformer is performed at 25 V, 50 HZ , the drown current is I1. If the test is performed by 25 V and 25 Hz and power drown current is I2 , then
a)    I1 > I2
b)    I1 < I2
c)    I1 = I2
d)    non of the above

7). Which of the following statements is /are correct statement ?
a)    For ideal Transformer efficiency is 100%
b)    For Ideal transformer voltage regulation is 100%
c)    both 1 and 2
d)    non of the above

8). Scott connections are used for
a)    single phase to three phase transformer
b)    three phase to single phase transformer
c)    three phase to two transformer
d)    any of the above

9). Two transformers operating in parallel will share the load depending on their
a)    Rating
b)    Leakage reactance
c)    Efficiency
d)    Per unit impedance

10). A 100/10 ,50 VA double winding transformer is connected to 100/110 V auto transformer. The rating of auto transformer is
a)    550 VA
b)    500 VA
c)    110 VA
d)    100 VA