PSC Junior Instructor – Electrician Solved Paper 2015 – Part 3

PSC Junior Instructor – Electrician Solved Paper 2015 – Part 3

Question 51:-_________ is the measure of how much potential difference the insulation layer can withstand without breaking down. A:-Insulation resistance B:-Breakdown voltage C:-Resistance D:-Dielectric strength Correct Answer:- Option-D Question 52:-The light output of Tin oxide Sodium lamps is in the order of A:-50 lumens/watt B:-45 lumens/watt C:-75 lumens/watt D:-150 lumens/watt Correct Answer:- Option-D Question 53:-The torque of a three phase induction motor is proportional to A:-square root of applied voltage B:-applied voltage C:-square of applied voltage D:-half of applied voltage Correct Answer:- Option-C Question 54:-Tap changing transformers are used for A:-stepping up the voltage B:-stepping down the voltage C:-both stepping up and stepping down the voltage D:-supplying low current for instruments Correct Answer:- Option-C Question 55:-Which Dc motor have negligible effect on speed with increase in torque? A:-DC differential compound motor B:-DC cumulative compound motor C:-DC series motor D:-DC shunt motor Correct Answer:- Option-D Question 56:-In a pure inductive AC circuit, the average true power is equal to A:-V x I watts B:-Zero watts C:-Square of current multiplied by reactance Watts D:-V x I volt amperes Correct Answer:- Option-B Question 57:-The part of an instrument which helps in leading in and leading out the current to the moving coil is A:-the spindle B:-the copper or aluminium disc C:-jewel bearing D:-control spring Correct Answer:- Option-D Question 58:-An outside micrometer can measure thickness and outside diameters to an accuracy of A:-±0.1mm B:-±0.5mm C:-±0.001mm D:-±0.01mm Correct Answer:- Option-D Question 59:-When a secondary battery is charged at 2% to 3% of normal rate for a long period, it is known as A:-boost charge B:-trickle charge C:-freshening charge D:-initial charge Correct Answer:- Option-B Question 60:-Double squirrel cage induction motors are used where ________ torque is essential. A:-high starting torque B:-low starting torque C:-low running torque D:-high running torque Correct Answer:- Option-A Question 61:-Which one of the following wiring circuit is not in accordance with IE rules? A:-Corridor wiring B:-Tunnel wiring C:-Godown wiring D:-Bank wiring Correct Answer:- Option-B Question 62:-The distance between the two active sides of a coil under adjacent dissimilar poles is called A:-coil pitch B:-winding pitch C:-pole pitch D:-pitch factor Correct Answer:- Option-A Question 63:-For the blocked rotor test of a 3 phase induction motor, the supply voltage should be limited to less than _______ percentage of rated voltage. A:-5% B:-10% C:-3% D:-20% Correct Answer:- Option-A Question 64:-The amount of heat required to increase the temperature of one kilogram of water through 1°C is A:-3187 joule B:-4187 joule C:-4187 calorie D:-3187 calorie Correct Answer:- Option-B Question 65:-Admittance is the reciprocal of A:-resistancve B:-conductance C:-reactance D:-impedance Correct Answer:- Option-D Question 66:-The damping winding in a synchronous motor is generally used A:-to provide starting torque only B:-to reduce noise level C:-to prevent hunting and to provide the starting torque D:-to reduce eddy currents Correct Answer:- Option-C Question 67:-Voltage dependent resistors are used as A:-as current stabilisers B:-as heating elements C:-to suppress surges D:-for inductive circuits Correct Answer:- Option-C Question 68:-In a DC generator, brush shifting is done to A:-alter the inter pole flux B:-alter the main field flux C:-neutralise the cross magnetising effect D:-neutralise the demagnetising effect Correct Answer:- Option-C Question 69:-To control a lamp from 4 positions, how many switches are required? A:-4 two-way switcges B:-4 intermediate switches C:-3 two-way switches and one intermediate switch D:-2 intermediate switches and 2 two-way switches Correct Answer:- Option-D Question 70:-The fusing factor for HRC fuse is A:-2.0 B:-1.7 C:-1.4 D:-1.1 Correct Answer:- Option-D Question 71:-Low and medium voltage underground cables should be laid at a depth of _______ from the ground surface to the top of the cable. A:-0.75m B:-0.9m C:-1.0m D:-1.05m Correct Answer:- Option-A Question 72:-For low and medium voltage overhead lines, the minimum clearance above ground, which is erected across a street, shall not be less than A:-5.791m B:-6.096m C:-5.486m D:-4.572m Correct Answer:- Option-A Question 73:-In capacitor start, capacitor run motors, the capacitors used are A:-both capacitors are of same value B:-one larger value capacitor of oil filled type and a smaller value capacitor of electrolytic type. C:-one larger value capacitor of electrolytic type and a smaller value capacitor of oil filled type. D:-both capacitors are of electrolytic type. Correct Answer:- Option-C Question 74:-While erecting a pole, the depth of pit below the ground level, in normal soil should be about _________ of the length of the pole. A:-1/6 B:-1/5 C:-1/4 D:-1/7 Correct Answer:- Option-A Question 75:-In an AC operated relay, the purpose of shading coil placed near the tip of magnetic pole face is to A:-eliminate chatter B:-eliminate humming C:-to reduce eddy current D:-to reduce hysteresis loss Correct Answer:- Option-A PSC Junior Instructor – Electrician Solved Paper 2015 – Part 1 PSC Junior Instructor – Electrician Solved Paper 2015 – Part 2 PSC Junior Instructor – Electrician Solved Paper 2015 – Part 3 PSC Junior Instructor – Electrician Solved Paper 2015 – Part 4