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Ircon Exam paper
1. Speed of the stator field of an Induction motor is
(A) Synchronous speed
(B) Any speed
(C) Less than Synchronous
(D) Slip Speed
Ans(A) Synchronous speed
2. Difference in speed between stator field and rotor
(A) Full load speed
(B)No load speed
(C)Slip
(D) Regulation
Ans:(C)Slip
3. FET is advantageous in comparison with BJT because of
(A) high input impedance.
(B) high gain-bandwidth product.
(C) its current controlled behaviour.
(D) high noise immunity.
Ans: A
4. The emission of electrons in a vacuum diode is achieved by
(A) electrostatic field.
(B) magnetic field.
(C) heating.
(D) electron bombardment.
Ans: C
5. In a Zener diode large reverse current is due to
(A) collision.
(B) presence of impurities.
(C) rupture of bonds
(D) lower resistance in reverse biased region.
Ans: D
6. JFET has main drawback of
(A) having low input impedance.
(B) having high output impedance.
(C) being noisy.
(D) Having small gain-bandwidth product.
Ans: D
7. The CE configuration amplifier circuits are preferred over CB configuration amplifier circuits because they have
(A) lower amplification factor.
(B) Larger amplification factor.
(C) high input resistance and low output resistance.
(D) none of these.
Ans: B
8. The most commonly used type of electron emission in electron tubes is
(A) Photo-electron emission.
(B) Thermionic emission.
(C) Field emission.
(D) Secondary emission.
Ans: A
9. After firing an SCR, the gating pulse is removed. The current in the SCR will
(A) Remains the same.
(B) Immediately fall to zero.
(C) Rise up.
(D) Rise a little and then fall to zero.
Ans: A
10. A device whose characteristics are very close to that of an ideal voltage source is
(A) a vaccum diode.
(B) a DIAC.
(C) a zener diode.
(D) a FET.
Ans: C
11. Which of the following is a unipolar device?
(A) P-N junction diode
(B) Zener diode
(C) Tunnel diode
(D) Schottky diode
Ans: D
12. On applying a Positive voltage signal to the base of a normally biased N-P-N CE transistor amplifier
(A) Base current will fall.
(B) Collector current will fall.
(C) Emitter current will fall.
(D) Collector voltage will become less positive.
Ans: D
13. A switching voltage regulator can be of the following type:
(A) step-down
(B) step-up
(C) inverting
(D) none of these
Ans: A
14. Avalanche breakdown is primarily dependent on the phenomenon of
(A) Collision
(B) Doping
(C) Ionisation
(D) Recombination
Ans: D
15. The ripple factor of a power supply is a measure of
(A) its voltage regulation.
(B) its diode rating.
(C) purity of power output.
(D) its filter efficiency.
Ans: C
16. An N-channel JFET has Pinch-off Voltage of VP = â 4V and given that VGS = â1V, then the minimum VDS for the device to operate in the Pinch-off region will be
(A) +1V
(B) +3V
(C) +4V
(D) +5V
Ans: B
17. The main advantage of flip-flops over transistor circuit is
(A) immunity from noise
(B) low heating
(C) low propagation delay time
(D) high propagation.
Ans:C
18. The ESC instruction of 8086 may have two formats. In one of the formats, no memory operand is used. Under this format, the number of external op-codes (for the co-processor) which can be specified is?
(A) 64
(B) 128
(C) 256
(D) 512
Ans:B
19. The voltage levels for a negative logic system
(A) must necessarily be negative
(B) could be negative or positive
(C) must necessarily be positive
(D) must necessarily be either zero or â5 V
Ans:B
20. The TRAP is one of the interrupts available its INTEL 8085. Which one of the following statements is true of TRAP?
(A) It is level triggered
(B) It is negative edge triggered
(C) It is positive edge triggered
(D) It is both positive edge triggered and level triggered
Ans:D
