Q.566 Resistance of bulb when connected to AC supply is ____ that of DC supply.
A. Less
B. Greater
C. Equal
D. Con not decide from the data
Ans.: B
Q. 567 The frequency of power in a purely resistive circuit fed by voltage source Vs=Vm sin wt (w=2лf) can be given as
A. f, same as frequency of input signal
B. If, twice that of frequency of input signal
C. Zero
D. None of the above
Ans.: B
Q, 568 Find the wavelength(λ) for a sinusoidal signal of 5 Hz.
A.6000 km
B.6 km
C.166 ηm
D.166 µm
Ans.: A
Q. 569 A 230/115V, 50Hz transformer is excited at 40 Hz from the 115V side. For the exciting current to remain the same, the applied voltage should be
A. 144 V
B. 92 V
C. 115 V
D.230 V
Ans.: B
Q. 570 If a balanced 3-phase winding is energized by balanced 3-phase supply then following magnetic field is created
A. Pulsating
B. Travelling
C. Stationary
D. None of the above
Ans.: B
Q. 571 For resistance R and Inductance L, the quality factor Q of the induction L that possesses a small resistance R can be given by, (W: angular frequency)
A.Q=R/WL
B. Q=R/L
C. Q=WL/R
D. Q=L/R
Ans.: C
Q. 572 The speed and torque of induction motor can be varied by which of the following means?
A. Stator voltage control
B. Rotor voltage control
C. Frequency control
D. All of these
Ans.: D
Q.573 A voltage source inverter is normally employed when
A. Source inductance is large and load inductance is small
B. Source inductance small and load inductance is large
C. Both inductances are large
D. Both inductances are small
Ans.: B
Q.574 Quantity factor of capacitor with capacitance of C and equivalent series resistance R and W is the frequency in radians at which the measurement is taken?
A. Q = 1/WCR
B. Q = WCR
C. Q = R/WC
D. Q = WC/R
Ans.: A
Q.575 The form factor of a pure sine wave
A. 1.414
B. 1
C. 1.11
D. 0
Ans.: C
Q.576 Corresponding to certain load connected to a 6-pole, 50 Hz wound rotor induction motor, frequency of current in rotor circuit is observed as 90 cycles per minute. Estimate the motor speed in rpm.
A.1030
B. 970
C. -1030
D. -970
Ans.: B
Q.577 The role of commutator in DC motor is
A. To reverse the current in the rotor conductor when it moves from North-pole to South pole
B. Not to reverse the current in the rotor conductor
C. To reduce the friction in the rotating part
D. None of the above
Ans.: A
Q.578 Find the number of roots in the left half of S-plane for the following equation s3 – 4s2 +s + 6 =0
A. one
B. Two
C. Three
D. Zero
Ans.: B
Q.579 Find the degree of following equation
A. Zero
B. One
C. Two
D. Four
Ans.: B
Q.580 What is the resonant frequency of LC circuit?
A. f = 1/2л√LC
B. f = 1/√LC
C. f = 2л√LC
D. f = √LC
Ans.: A