MCQ Questions. Elements of Electrical Engineering (EEE)

Transcription

1 MCQ Questions 1. The length of conductor is doubled and its area of cross section is also doubled, then the resistance will. a. Increase four time b. Remain unchanged c. Decrease to four times d. Change at random 2. An electric lamp is rated 100 W,220 V. the resistance of the filament will be. a. 22 ohm b ohm c. 484 ohm d ohm 3. The rating of four electric appliances is given below: Washing Machine-3000 W,230 V; Electric Lamp- 100 W,230 V; Room Heater-1500 W,230 V; Electric fan- 80 W,230 V; Which appliance would require thickest lead wire? a. Washing machine b. Electric lamp c. Room Heater d. Electric fan 4. Which of the following quantities are same in all parts of series circuit? a. Voltage b. Power c. Current d. Resistance 5. How are 500 ohm resistors connected so as to give an effective resistance of 750 ohm.. a. Three resistance of 500 ohm each, in b. Three resistance of 500 ohm each, in series parallel c. Two resistance of 500 ohm each, in parallel 6. Kirchhoff s voltage law states that a. The total voltage drop in a series circuit is always finite c. The sum of e.m.f.s in closed mesh is d. Two resistance of 500 ohm each, in parallel and the combination in series with another 500 ohm resistance b. The algebraic sum of e.m.f.s. and voltage drops in a closed mesh is zero d. The sum of voltage drops and e.m.f.s in a mesh is zero. zero. 7. An ideal source should have a. Zero internal resistance b. Infinite internal resistance. c. Large value of e.m.f d. None of above 8. A network which does not have either voltage sources or sources is called a. Active network b. Passive network c. Resistive network d. Dummy network 9. Which of the following is an active element in a circuit? a. Current source b. Resistance c. Inductance d. Capacitance 10. Which of the following is not bilateral element? a. Constant source b. Resistor c. Inductor d. Capacitor 11. The nodal analysis is primarily based on the application of a. Ohm s law b. Kirchhoff s law c. Kirchhoff s voltage law d. Both a and b 12. In the node-voltage technique of solving network, choice of reference node a. Affects the voltage of various nodes b. Affects the operation of the circuit c. Changes the voltage across any element d. Alter the potential difference between any pair of nodes.

2 13. A length of wire having a resistance of 1ohm is cut into four equal parts. There four parts are bundled together side by side to form a thicker wire. The resistance of the thicker wire will be a. 4 ohm b. 1/16 ohm c. ¼ ohm d. 16 ohm 14. Electrostatics is the branch of engineering which deals with a. The flow of through semiconductors b. The charged bodies separated by dielectric medium c. The flow of through d. The DC circuit only. capacitance. 15. The relation between D and E is given by the expression a. D = Ɛ 0Ɛ re b. E=Ɛ 0Ɛ rd c. D= E/Ɛ 0Ɛ r d. None of above 16. To move a unit positive charge from one to another point on an equipotential surface a. Work is done by the charge b. Work is done on the charge c. No work is done d. Work done is constant 17. Dielectric strength of a medium depends on---- a. temperature b. thickness c. moisture content d. all of these 18. The value of electric field intensity within the field due to a point charge can be determined by a. Gauss s Law b. Ampere s Law c. Coulomb s Law d. Maxwell s Law 19. If the dielectric slab of thickness 5 mm and Ɛ r = 6 is inserted between the plates of an air capacitor with plate separation of of 8mm,its capacitance is---- a. decreased b. almost doubled c. almost halved d. unaffected 20. The number of 1μf capacitors needed to be connected in parallel in order to store a charge of 1 c with a p.d of 500 v across the capacitors is.. a. 500 b c d. None of above 21. If the dielectric of a capacitor is replaced by a conducting material, a. Capacitor will get heated up owing to b. Plates will get short circuited eddy c. Capacitor can store infinite charge d. Capacitance will become very high 22. The charge on an isolated conductor resides. a. At the conductor surface b. Inside the conductor c. Partly at the conductor surface and d. None of the above partly inside the conductor 23. A parallel plate capacitor has air as dielectric. The p.d between two plates of the capacitor is 200 V. if a dielectric constant 5 is now introduced fully between the plates then the voltage across the capacitor.. a. Becomes 40 V b. Becomes 1000 V c. Becomes 5000 V d. Remains 200 V as before 24. For making a capacitor, it is better to select a dielectric having a. High permittivity b. Low permittivity c. Permittivity same as that air d. None of above 25. To reduced the eddy loss in the core of magnetic material

3 a. The core is laminated b. The material used should have high resistivity c. Solid core is used d. Both a. & b. 26. The permanence in a magnetic circuit corresponds to a. Resistance in electric circuit b. EMF in electric circuit c. Conductivity in electric circuit d. Conductance in an electric circuit 27. The direction of electromagnetically induced EMF is determined by a. Flemings right hand rule b. Lenz s Law c. Right hand thumb rule d. Both a. & b. 28. The principle of dynamically induced EMF is utilized in a a. Choke b. Motor c. Generator d. Battery 29. Hysteresis loss in a magnetic material depends on a. Area of hysteresis loop b. Frequency of reversal of field c. Volume of magnetic material d. All a,b and c 30. Mutual inductance between two magnetically coupled coils depends on the a. Permeability of the core material b. Number of turns of the coil c. Cross sectional area of their common d. All of the above core 31. If the length, number of turns and area of coil are doubled, the inductance of coil is a. same b. doubled c. quadrupled d. one quartered 32. Which of the following inductors will have the least eddy losses? a. air cored b. ion cored c. laminated core d. none of the above 33. Lower the self inductance of the coil a. more will be the weber turn b. more will be the EMF induced c. lesser the flux produced by it d. smaller the delay in establishing through it 34. The self induced EMF of the coil of N turns is proportional to a. N b. N 2 c. 1/N d. 1/N The materials having low retentivity are suitable for making magnets a. Permanent. Temporary b. Weak c. Strong 36. If a 10 Ohm resistance is connected to an AC source V=100 sin (314t + 30), the power dissipated is a Watt b. 500 Watt c Watt d. 250 Watt 37. What will happen if the frequency of the power supply in a pure capacitive circuit is doubled? a. The will also be doubled b. The will reduce to half c. The will remain the same d. The will increase to four fold 38. Purely inductive circuit takes power from the AC mains when a. Both applied voltage and b. Both applied voltage and decrease increase c. Applied voltage decreases but increases 39. A series resonance circuit implies d. Applied voltage increases but decreases

4 a. Zero power factor & maximum b. Unity power factor & maximum c. Unity power factor & minimum d. Zero power factor and minimum 40. In series as well as parallel resonance circuit, increase in resistance would cause a. Increase in bandwidth of both the b. Decrease in bandwidth of both the circuits circuits c. Decrease in bandwidth in series circuit and increase and increase in bandwidth in parallel circuit d. Decrease in bandwidth in series circuit and decrease in bandwidth in parallel circuit 41. An R-L-C parallel circuit in resonance will. a. Have a high impedance b. Act like a resistor of low value c. Have in each branch equal to that of the line d. produce lot of noise and heat 42. In an ac circuit Icosφ is called the. a. Wattles or reactive component of b. quadrature component of c. active and useful component of d. none of above 43. Which of the following statement associated with 3-phasedelta connected circuits is TRUE a. line voltage is equal to phase voltage b. line is equal to phase c. line voltage is 3 times the pahse d. Line s re 60 apart. voltage 44. The power delivered to a three phase lod can be measured by the use of two wattmeters only when the a. Load is balanced b. Load is unbalanced c. 3-phase load is connected to the source through 3-wire d. 3-phase load is connected to the source through 4-wire. 45. Three equal impedances are connected in delta across a 3-phase balanced supply. If the same impedance are connected in star across the same supply a. Phase s will be one third b. Line s will be one third c. Power consumed will be one third d. none of the above 46. In two wattmeter method of power measurement, one of the wattmeters will show negative reading when the load power factor angle is strictly. a. Less than 30 b. Less than 60 c. Greater than 30 d. Greater than In a three phase supply, floating neutral is undesirable because it may result in.. across the load. a. Unequal line voltages b. High voltage c. Low voltage d. Any of the above 48. In two wattmeter method of 3-phase power measurement, one of the wattmeters gives down scale reading, when the power factor is a. unity b. 0.5 c. Between 1 and 0.5 d. Between zero and When three 10 ohm resistors are connected in star across a 400 v, 3-phase supply, each resistor must have power rting. a w b w c w d w 50. A three phase load is said to be balanced load, if all the three phase have the same..

5 a. impedance b. power factor c. both a and b d. none of above