Multiple Choice Questions for Electronics Engineering Part 3

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Q.36 In a bridge rectifier

  1. PIV has a value Vm

  2. Centre tap of secondary is not required

  3. Smaller transformer can be used

  4. All

Answer: 4

Q.37 In an R-2R ladder D/A converter, the input resistance is

  1. Not same for all digital inputs

  2. R for each input

  3. 2R for each input

  4. 3R for each input

Answer: 4

Q.38 The speed of a D.C. motor can be controlled by varying

  1. Its flux per pole

  2. Resistance of armature circuit

  3. Applied voltage

  4. All of the above

Answer: 4

Q.39 The chief advantage of Ward-Leonard system D.C motor speed control is that is

  1. Can be used even for small motors

  2. has high overall efficiency at all speeds

  3. Gives smooth, sensitive and wide speed control

  4. Uses a flywheel to reduce fluctuations in power demand

Answer: 3

Q.40 A transformer transforms

  1. Frequency

  2. Voltage

  3. Current

  4. Voltage and current

Answer: 4

Q.41 Which of the following is not a basic element of a transformer?

  1. Core

  2. Primary winding

  3. Secondary winding

  4. Mutual flux

Answer: 4

Q.42 The slight curvature at the lower end of the O.C.C. of a self-excited dc generator is due to

  1. residual pole flux

  2. high armature speed

  3. magnetic inertia

  4. high field circuit resistan

Answer: 3

Q.43 for the voltage built-up a self-excited D.C. generator, which of the following is not an essential condition.

  1. there must be some residual flux

  2. field winding mmf must aid the residual flux

  3. total field circuit resistance must be less than t critical value

  4. armature speed must be very high

Answer: 4

Q.44 The Intel 8212 is an - non programmable I/O port

  1. 4 – bit

  2. 8 – bit

  3. 16 – bit

  4. 32 – bit

Answer: 2

Q.45 The terms 'soft sectored' and 'hard sectored' are used in connection with

  1. µP

  2. RAM

  3. ROM

  4. Floppy disk

Answer: 4

Q.46 In temperature monitoring system – transducers are used

  1. 2

  2. 3

  3. 4

  4. 6

Answer: 1

Q.47 Today most computers use-technology for their operation

  1. Germanium

  2. Silicon

  3. Gallium – Arsenide

  4. Gallium – telluride

Answer: 2

Q.48 In a multivibrator

  1. Feedback between two stages is 100%

  2. Positive feedback is employed

  3. When one transistor is on, the other is off

  4. All

Answer: 4

Q.49 An OP-AMP can be classified as

  1. Linear amplifier

  2. Low – Rin amplifier

  3. Positive – feedback amplifier

  4. RC – coupled amplifier

Answer: 2

Q.50 Amplification factor of a circuit is 50. For oscillator is feedback factor should be

  1. 50

  2. 100

Answer: 3

Q.51 positive feedback is used in

  1. Amplifier

  2. Rectifier

  3. Oscillator

  4. Detector

Answer: 3

Q.52 Darlington pair

  1. is a three terminal device with very high current gain

  2. has a very high input impedance

  3. has a very low output

  4. all the above are true

Answer: 4

Q.53 Which of the following has got a positive susceptibility

  1. Diamagnetic

  2. Paramagnetic

  3. Ferromagnetic

  4. both paramagnetic & ferromagnetic

Answer: 4