ECET EEE Model Paper-1 Part9

1. The maximum efficiency of a full wave rectifier is around

A. 90%
B. 81%
C. 40%
D. None of the above

Answer : 81%
Explanation:-

2. One of the serious disadvantage of FM transmission is

A. High static noise
B. Limited line-of sight range
C. Expensive equipment
D. Adjacent channel interference

Answer : Limited line-of sight range
Explanation:-

3. A thyristor can be fermed as

A. D.C. switch
B. A.C. switch
C. Either A and B
D. Square wave switch

Answer : Either A and B
Explanation:-

4. Each diode of a 3-phase half-wave diode rectifier conducts for

A. 60°
B. 120°
C. 180°
D. 90°

Answer : 120°
Explanation:-

5. Boolean algebra is essentially based on

A. Symbols
B. Logic
C. Truth
D. Numbers

Answer : Logic
Explanation:-

6. The dual of statement (A+1)=1 is

A. A.1=A
B. A.0=0
C. A+A=A
D. A.A=1

Answer : A.0=0
Explanation:-

7. Noice margin is expressed in

A. Decibel
B. Watt
C. Volt
D. Phon

Answer : Volt
Explanation:-

8. In amplitude modulation

A. Carrier frequency is changed
B. Three side bands are produced
C. Carrier amplitude is changed
D. Fidelity is improved

Answer : Carrier amplitude is changed
Explanation:-

9. For sustaining oscillations in an oscillator

A. Feedback factor should be unity
B. Feedback factor should be negative
C. Phase shift should be 0°
D. Both A and B

Answer : Both A and B
Explanation:-

10. An ideal amplifier has

A. Noise figure of less than 1 dB
B. Noise factor of unity
C. Output S/N more than input S/N
D. Noise figure of more the 0 Db

Answer : Noise factor of unity
Explanation:-