# Power electronics

Power electronics
Question:-
Option (A)
Option (B)
Cycloconverter
Option (C)
Inverter
Option (D)
bi-directional rectifier
Correct Option:
B
Question Solution:
A cycloconverter changes the frequency which is not possible with a chopper
Question:-
Option (A)
0.64
Option (B)
0.8
Option (C)
0.894
Option (D)
Difficult to estimate because of insufficiency of data
Correct Option:
B
Question Solution:
p.f. = (Vor/Vs) = (200/250) = 0.8
Question:-
Option (A)
Both A and R are true and R is the correct explanation of A
Option (B)
Both A and R are true but R is not the correct explanation of A
Option (C)
A is true but R is false
Option (D)
A is false but R is true
Correct Option:
A
Question Solution:
Induced emf a Æ.f which suggests that at high frequency, transformer core size reduced
Question:-
Option (A)
dv/dt problem
Option (B)
di/dt problem
Option (C)
the size of the pulse transformer
Option (D)
the complexity of the firing circuit
Correct Option:
C
Question Solution:
Refer, explanation of question no 2
Question:-
Option (A)
6 ms
Option (B)
4 ms
Option (C)
2 ms
Option (D)
1 ms
Correct Option:
B
Question Solution:
E=L.(di/dt)
\ t= (i.L/E) = {(4 x 10-3x0.1)/100} = 4 ms