Electronic Engineering MCQ Question Papers: ENTC, IT Interview Placement

Subject: Network Theory 6

**Part 6: List for questions and answers of Network Theory**

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**Q1. If the iron core of a coil is removed so that it becomes an air cored coil, its inductance**

**a) Will increase**

**b) Will decrease**

**c) Will remain the same**

**d) May increase or decrease**

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**Q2. A square current wave of magnitude 1 A is applied to an element for 5 seconds. The ****voltage across the element rises linearly from 0 to final value linearly. The element is**

**a) Resistance**

**b) Inductance**

**c) Capacitance**

**d) R and C in series**

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**Q3. A periodic voltage v(t) = 1 + 4 sin wt + 2 cos wt is applied across a 1 ohm resistance. ****The power dissipated is**

**a) 1 W**

**b) 11 W**

**c) 21 W**

**d) 24.5 W**

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**Q4. A coil is wound having a diameter d. Its inductance is 10 mH. If it is rewound on the ****same core with a wire having diameter 0.5 d and total weight of the wire is the same as ****before, the inductance will be**

**a) 5 mH**

**b) 10 mH**

**c) 160 mH**

**d) 40 mH**

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**Q5. Permeability is analogous to**

**a) Conductivity**

**b) Resistivity**

**c) Retentivity**

**d) Coercivity **

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**Q6. A 10 uF capacitor is charged from a 5 volt source through a resistance of 10 k ohm. The ****charging current offer 35 m sec. If the initial voltage on C is – 3 V is**

**a) 0.56 mA**

**b) 5.6 mA**

**c) 6 mA**

**d) 5 uA**

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**Q7. If an admittance Y(s) has a term Ks, the realization would give**

**a) An inductance of value K**

**b) A resistance of value K**

**c) A capacitance of value K**

**d) Either (a) or(c)**

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**Q8. If the diameter of a wire is doubled, the current carrying capacity of the wire becomes**

**a) Half**

**b) Twice**

**c) Four times**

**d) One-fourth**

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**Q9. Two voltages 50 V each have a phase difference of 45°. The rms value of resultant sum ****of the two voltages is**

**a) 70.7 V**

**b) 80.4 V**

**c) 92.4 V**

**d) 100 V**

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**Q10. The energy stored in a coil is 108 J. It is opened suddenly in 10 ms. The power ****dissipated instantaneously across the blades of switch is**

**a) 108 W**

**b) 1080 W**

**c) 10800 W**

**d) 108000 W**

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**Q11. A magnetic circuit has an iron length of 20 cm and air gap length 0.1 cm. If uf = 200 ****then**

**a) mmf for iron and air gap are equal**

**b) mmf for iron is much less than that for air gap**

**c) mmf for iron is much more than that for air gap**

**d) either (a) or (c) **

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**Q12. Two coils X and Y have self inductances of 5 mH and 10 mH and mutual inductance of 3 ****mH. If the current in coils X change at a steady rate of 100 A/s, the emf induced in coil Y is**

**a) 0.3 V**

**b) 0.5 V**

**c) 1 V**

**d) 1.5 V**

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**Q13. Two capacitors of 2 uF and 4 uF capacitance are connected in series across a 30 V dc ****battery. After the capacitors have been charged, the voltage across them will be**

**a) 15 V each**

**b) 10 V and 20 V**

**c) 20 V and 10 V**

**d) 30 V each**

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**Q14. A 50 Hz current has an amplitude of 10 A. The rate of change of current at t = 0.005 ****after i = 0 and is increasing is**

**a) 2221.44 A/s**

**b) 0**

**c) 2221.44 A/s**

**d) 3141.6 A/s**

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**Q15. An RLC series circuit is fed form 100 V ac supply. Inductance is 1 H and Q = 7.5. At ****resonance, the voltage across inductance is**

**a) 750 V**

**b) 100 V**

**c) about 13.5 V**

**d) 1500 V**

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**Q16. As temperature increases, the temperature coefficient of a metal**

**a) Decreases**

**b) Increases**

**c) Remains unchanged**

**d) Any of the above**

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**Q17. A wire has a resistance R ohm. If another wire of the same material and same weight ****has double the diameter (as compared to the first wire), the resistance of the second wire ****will be**

**a) 0.5 R**

**b) 0.25 R**

**c) 0.125 R**

**d) R/16 **

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**Q18. Volt is equivalent to**

**a) Joule/coulomb**

**b) Joule/watt**

**c) Joule/ampere**

**d) Joule/volt**

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**Q19. A two branch parallel tuned circuit has a capacitance C in one of the two branches and ****resistance R in second branchs. As C is decreased the dynamic resistance**

**a) Increases**

**b) Decreases**

**c) Remains constant**

**d) May increases or decreases**

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**Q20. In an R-C circuit, the impedance is 40 ohm at a frequency of 100 Hz. At 200 Hz the ****impedance should be**

**a) 40 ohm**

**b) 80 ohm**

**c) 20 ohm **

**d) More than 20 ohm but less than 40 ohm**

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**Part 6: List for questions and answers of Network Theory**

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**Q1. Answer: b**

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**Q2. Answer: c**

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**Q3. Answer: b**

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**Q4. Answer: c**

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**Q5. Answer: a**

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**Q6. Answer: a**

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**Q7. Answer: a**

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**Q8. Answer: c**

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**Q9. Answer: c**

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**Q10. Answer: c**

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**Q11. Answer: a**

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**Q12. Answer: a**

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**Q13. Answer: c**

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**Q14. Answer:**

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**Q15. Answer: a**

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**Q16. Answer: a**

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**Q17. Answer: d**

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**Q18. Answer: a**

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**Q19. Answer: a**

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**Q20. Answer: d**