Mcqs in Basic Electronics​ test paper

 1.When four resistances of 2W 1W; 5W 2W; 10W 5W and 15W 10 W are connected in parallel, the greatest power is absorbed by

• 2 W, 1 W         
• 5 W, 2 W         
• 10 W, 5W        
• 15 W, 10 W

 2. A moving coil instrument has a resistance of 10 W and gives full scale deflection when carrying a current of 50 mA.  To measure current upto 100 A, we will have to connect  

• 10 W resistance in series
• 10 W resistance in parallel
• 10/1999 W resistance in series
• 10/1999 W resistance in parallel

 3. The ripple voltage in the output of a single phase half wave rectifier with 10 V rectified dc voltage with resistive load and without filter will be 

• 12.1 volt
• 1.21 volt
• 0.482 volt
• 4.82 volt

 4. The transformer connection which has gained considerable popularity to serve 3-phase equipment and single phase lighting load is  

• Star/Star
• Delta/Delta
• Delta/Star
• Star/Delta

 5. Transformer oil tester is used to know 

• Permittivity
• Permeability
• Dielectric strength
• Resistance of the oil

 6. Plate separation of a parallel plate air capacitor is reduced keeping the voltage constant.  The energy stored in the capacitor shall 

• Increase
• Decrease
• Remain constant
• Remain zero

 7. 1 Ampere of current is defined as  

• 1 volt/sec
• 1 coulomb/sec
• 1 ohm/second
• 1 coulomb

 8. The synchronous motor can be used as a capacitor 

• By increasing excitation
• By decreasing excitation
• By increasing speed
• By decreasing speed

 9. The actual speed of an induction motor is always  

• Less than synchronous speed
• More than synchronous speed
• Equal to synchronous speed
• None of the above. 

 10. The purpose of connecting a capacitor in flourescent tube circuit is 

• To increase switching on time
• To decrease switching off time
• To increase power factor
• To decrease power consumption

 11. The condition for parallel operation of two inverters is  

• Amplitude of voltages should be same.
• Frequency of voltages should be same.
• Both the voltages should be in same phase.
• All the three above.

12. A 60 Hz, 2 pole alternator should run at 

• 3000 r.p.m.
• 1500 r.p.m.
• 3600 r.p.m.
• 1800 r.p.m. 

13.The purpose of a governer in a DG set is 

• To regulate the speed.
• To regulate the voltage
• To regulate the power
• To regulate the current. 

14.       A   S C R can conduct 

• In one direction only.
• In both directions.
• Only when gate is triggered.
• None of the above.

 15.The cut-in voltage of a silicon diode is approx. 

• 0.7 volt
• 0.3 volt
• 1.4 volt
• None of the above. 

16. The step Recovery Diode is used as  

• Frequency adder
• Frequency subtractor
• Frequency multiplier
• None of the above.

 17. The isolation between input and output in case of opto coupler is of the order of  

• 10 Ohms                                
• 10¹⁰ ohms
• 10³ ohms                                
• None of the above. 

 18. The transistor configuration to connect 4 W speaker with 600 W output impedance audio amplifier is 

• Common Emitter
• Common Base
• Common Collector
• None of the above.  

 19. Beta cut-off frequency of a transistor is the frequency at which the Beta is 

• 0.707 of low frequency value
• Zero
• Equal to low frequency value
• None of the above.

 20. Which of the following amplifier has the least distortion. 

• Class E
• Class D
• Class C
• Class A

 21. Pinch off voltage of a J FET is the drain to source voltage above which drain current. 

• Increases
• Decreases
• Remains constant
• Becomes zero 

22. Decimal equivalent of binary 1111 1111 1111 1111 is 

• 16,384
• 65,536
• 1000000
• None of the above. 

23. A l/2 dipole aerial is used for 

• MW
• SW
• Microwave
• None of the above. 

24. TCXO is preferred over LC oscillator because 

• TCXO is more stable.
• TCXO gives more power
• TCXO is linear.
• None of the above.

 25. The angular velocity of geo-stationary satellite is 

• Equal to the angular velocity of earth.
• Less than the angular velocity of earth.
• More than the angular velocity of earth
• None of the above.  

 26. The battery operated pre-amplifier with a consumption of 10 Watts can work on battery of 12 volt, 100 AH having efficiency of 50% for 

• 120 hrs.
• 60 hrs.
• 100 hrs.
• 10 hrs.

 27. Low pass filter with cut off frequency of 100 kHz and high pass filter with cut off frequency of 50 kHz are connected in tandem, the resultant filter is 

• Low pass filter with cut off frequency of 100 kHz
• High pass filter with cut off frequency of 50 kHz
• Band pass filter with pass band from 50 kHz to 100 kHz.
• None of the above.

 28. In case of oil fire, the fire extinguisher used is 

• Soda Acid
• Foam
• Carbon dioxide
• Carbon Tetra chloride 

29. The output of a 2-input NAND gate with high at both the inputs will be  

• High
• Low
• High & low
• None of the above.

 30. The input impedance of an op-amp is 

• High
• Low
• Medium
• None of the above

Answers Mcqs in Basic Electronics​

1(a), 2 (d), 3 (a), 4 (c), 5 (c) 6 (a) 7 (b) 8 (a) 9 (a) 10 (c) 11 (d) 12 (c) 13 (a) 14 (a) 15 (a)

16 (c) 17 (b) 18 (c) 19 (a) 20 (d) 21 (c) 22 (b) 23 (b) 24 (a) 25 (a) 26 (b) 27 (c) 28 (b) 29 (b) 30 (a).