CHAPTER 18 ELECTRONICS
CHAPTER 18
ELECTRONICS
(a) there is an immediate recombination of holes with electrons
(b) there is an immediate diffusion of charge carriers across the
junction
(c) more and more charge carriers are produced
(d) none of these
2. Depletion voltage
(a) is more for germanium
(b) increases in the forward bias
(c) decreases with reverse bias
(d) is more for silicon
3. Reverse biasing of a PN-junction is obtained by
connecting
(a) P-side of the junction with positive terminal of the battery
(b) N-side of the junction with negative terminal of the battery
(c) N-side of the junction with positive terminal of the battery
(d) both P and N sides of the junction with ground.
4. Avalanche breakdown
(a) refers to forward bias region
(b) refers to reverse bias region
(c) takes place in heavily doped junctions
(d) none of these
5. Depletion region carries
(a) positive charges
(b) negative charges
(c) no charge
(d) all of these
6. Potential barrier in a diode
(a) helps moving holes from P-type to N-type
(b) helps moving electrons from N-type to P-type
(c) stops the mutual movement of both hole and electrons
(d) none of the above
7. The graph which shows the relation of biased voltage
versus current through a P-N junction is called
(a) diode current graph
(b) diode voltage graph
(c) diode graph
(d) current biased voltage graph
8. If a reverse current of a reverse biased junction is
increased to a maximum value then
(a) voltage drops to zero
(b) diode becomes more efficient
(c) diode junction may break down
(d) none
9. Process of conversion of AC into DC is called
(a) rectification
(b) amplification
(c) purification
(d) magnification
10. Conversion of only one half of AC into DC is called
(a) half wave amplification
(b) full wave amplification
(c) half wave rectification
(d) full wave rectification
11. Identify which instrument can be used for rectification
(a) Transistor
(b) Diode (or p-n junction)
(c) Inductor
(d) Transformer
12. In a half wave rectifier, the diode conducts for
(a) the full input cycle
(b) a portion of the positive half of the input cycle
(c) a portion of the negative half of the input cycle
(d) one half of the input cycle
13. In full-wave rectification by bridge the number of diodes
required are
(a) only one
(b) two only
(c) four
(d) infinite
14. LED's work on the basis of
(a) emission of energy in the form of photons
(b) Faraday's law
(c) ionic bonding between P-type & N-type substance
(d) none
15. The central region of a N-P-N transistor is called
(a) collector
(b) base
(c) emitter
(d) barrier
16. The ratio of collector current IC to the base current IB is
always constant for a given transistor. This ratio is
called
(a) resultant current of a transistor
(b) multiple current of a transistor
(c) current gain of a transistor
(d) none
17. For a normal biased transistor, the emitter current IE can
be given by
(a) IE = IC
(b) IE = IB
(c) IE = IC + IB
(d) none of these
18. Conversion of small AC voltage into large AC voltage is
(a) rectification
(b) magnification
(c) amplification
(d) all of the above
19. In a PN junction the arrow points towards
(a) P side
(b) N side
(c) depletion region
(d) the direction of electron flow
20. In the forward region of its characteristics, a junction
diode appears as
(a) an OFF switch
(b) an ON switch
(c) a high resistance
(d) good conductor
21. In a P-N junction, the diffusion current is
(a) from N side to P side
(b) from P side to N side
(c) zero
(d) due to minority carriers
22. In a P-N junction with no applied voltage
(a) there is a net charge transfer between the two sides
(b) there is a constant electric field near the junction
(c) there is no net charge transfer between the two sides
(d) none of these
23. In the normal use of transistor,
(a) the emitter is forward biased
(b) the emitter is reversed biased
(c) the collector is forward biased
(d) the base is reverse biased
25. In common base configuration, a transistor amplifier has
(a) a high input resistance
(b) a low input resistance
(b) a low output resistance
(d) none of these
26. A common-base transistor amplifier is one in which
(a) emitter is grounded
(b) base is grounded
(c) collector is grounded
(d) output is obtained across the base.
27. In a common-emitter amplifier, the phase difference
between output and input voltage is
(a) 0°
(b) 90°
(c) 180°
(d) none of these
28. Beta is the current gain in
(a) common base amplifier
(b) common emitter amplifier
(c) common collector amplifier
(d) oscillator
29. Two terminals of op-amp are respectively called
(a) negative input (–) and positive input (+)
(b) negative input (–) and positive output (+)
(c) negative output(–) and positive input (+)
(d) inverting input (–) and non-inverting input(+)
31. Truth table of a logic gate
(a) summarizes its output values
(b) tabulates all its input conditions
(c) display all its input / output possibilities
(d) is based on number algebra
32. An AND gate
(a) performs logic addition
(b) performs logic multiplication
(c) has output true if one of its input is true
(d) none of these
33. A two-input OR gate
(a) has an output O if either of its input is1
(b) has output 1 if both its inputs are 0
(c) performs logic multiplication
(d) has output 1 if either of its inputs is 1.
34. A NAND gate
(a) is an AND gate with inverted inputs
(b) is an AND gate with inverted outputs
(c) gives output 1 for both its inputs at 1
(d) gives output O for both its inputs at O
35. A NOR gate
(a) has an output 1 if both its inputs are 1
(b) has an output 1 if both its inputs are 0
(c) is an OR gate with inverted inputs
(d) is a combination of AND and OR gates
36. A NOT gate
(a) has two inputs
(b) has two outputs
(c) has one input
(d) has one input and one output
37. In a 2-input logic gate, both inputs are 0. If output is 1,
gate could be
(a) on OR only
(b) a NOR only
(c) a NAND only
(d) a NOR, NAND or XNOR
38. Which of the following gates are universal?
(a) OR
(b) AND
(c) NOT
(d) NAND and NOR
39. Any logical expression can be realized using only
(a) AND gate
(b) NAND gate
(c) AND, OR and NOT gate
(d) NOT gate
40. An AND gate can be prepared by repetitive use of
(a) OR gate
(b) NOR gate
(c) NAND gate
(d) Both NOR and NAND gates