MCQ on Electronics and Communication Engineering

1-The ripple frequency of the output wave form of bridge rectifier with a 60 Hz sine wave is
(A) 100 Hz
(B) 120 Hz
(C) 30 Hz
(D) 60 Hz
 
2-One kwh is equal to
(A) 860 kcal
(B) 800 kcal
(C) 746 kcal
(D) 736 kcal
 
3-A 100W bulb, a 40W fluorescent lamp and a 60W fan in a room operates for an average duration of 5 hours in a day. What will be the total energy consumed during the month of June 2017?
(A) 3 kwh
(B) 30 kwh
(C) 300 kwh
(D) 3000 kwh
 
4-An alternating current is represented by I=141sin314t. What is the rms value of this current?
(A) 314 A
(B) 141 A
(C) 100 A
(D) 70.5 A
 
5-Which of the following is not a possible cause for optical fiber lose?
(A) Impurities
(B) Attenuation in glass
(C) Stepped index operation
(D) Micro-bending
 
6-Thermocouple works on the principle of
(A) Seebeck effect
(B) Piezoelectric effect
(C) Photo voltaic effect
(D) Faraday effect
 
7-Change in the resistance caused by strain is ΔR, the resistance of the undeformed gauge is R and ϵ is the strain. The gauge factor is
(A) (ΔR/R)/ϵ
(B) ϵ ΔR/R
(C) ϵ/ΔRR
(D) ΔRR/ϵ
 
8-LEDs are made out of
(A) Silicon
(B) Germanium
(C) Gallium Arsenide
(D) Silicon and Germanium
 
9-What are the health hazards which can be caused by E-waste, if it is not properly treated or disposed off?
(A) Brain damage
(B) Lung cancer
(C) DNA damage
(D) All of the above
 
10-Which of the following is not a mode of operation of piezoelectric transducer?
(A) Transverse
(B) Longitudinal
(C) Shear
(D) Elastic
 
11-Light travelling in an optical fiber follows which of the following principle?
(A) Huygens principle
(B) Light theory
(C) Snell’s law
(D) Fermat’s principle
 
12-Which of the following is an inductance variable type transformer?
(A) LVDT
(B) Load cell
(C) Thermistor
(D) Carbon microphone
 
ANSWERS:
1-(B), 2-(A), 3-(B), 4-(C), 5-(C), 6-(A), 7-(A), 8-(C), 9-(D), 10-(A), 11-(C), 12-(A)