LDC Syllabus 2020

# PSC Junior Instructor – Electrician Solved Paper 2015 – Part 4

Last Updated On: 30/04/2018

## PSC Junior Instructor – Electrician Solved Paper 2015 – Part 4

Question 76:-To test an armature for the short circuited coils, ________ is used along with the growler.
A:-milli-voltmeter
C:-ohm meter
D:-meggar

Question 77:-The type of fire extinguisher used where liquified gas is on fire is
A:-water filled fire extinguisher
B:-dry powder extinguisher
C:-foam type fire extinguisher
D:-carbon dioxide fire extinguisher

Question 78:-Earthing one of the wires of electrical system, to limit the maximum voltage to earth under normal operating conditions is known as
A:-equipment earthing
B:-system earthing
C:-generator earthing
D:-substation earthing

Question 79:-To measure the earth electrode resistance, the current and pressure spikes of the earth resistance tester are to be driven into the ground at a distance of ______ from the main electrode under test.
A:-20m and 10m apart respectively
B:-25m and 12.5m apart respectively
C:-20m and 10m apart respectively in a straight line
D:-25m and 12.5m apart respectively in a straight line.

Question 80:-The type of joint used for overhead lines for tapping the electrical energy perpendicular to the service line is
A:-knotted tap joint
B:-aerial tap joint
C:-tee joint
D:-britannia tee joint

Question 81:-According to BIS and NEC, the clearance between the bottom point of the ceiling fan and the floor shall not be less than
A:-2.5m
B:-2.75m
C:-2.25m
D:-2.4m

Question 82:-If firing angle in an SCR rectifier is increased, the output is
A:-remains same
B:-SCR is turned off
C:-decreased
D:-increased

Question 83:-Which electrode of the CRT mainly controls the brightness of the image on the screen?
A:-Anode
B:-Cathode
C:-Control grid
D:-Focusing electrodes

Question 84:-Efficiency of a transformer is maximum, when
B:-hysteresis loss is equal to eddy current loss
C:-copper loss is equal to eddy current loss
D:-copper loss is equal to iron loss

Question 85:-For the parallel operation of two transformers, the phase sequence must be identical, otherwise, during the cycle
B:-impossible to take the full load output without excessive heating of one of the transformer
C:-each pair of phases will be open circuited
D:-each pair of phases will be short circuited

Question 86:-A two layer lap wound 4 pole generator with 16 coils will have a pole pitch of
A:-32
B:-16
C:-8
D:-4

Question 87:-The maximum safe temperature for class F insulating material is
A:-155°C
B:-130°C
C:-120°C
D:-180°C

Question 88:-The ratio of intensity of magnetisation to the magnetising force is known as
A:-permeability
B:-permittivity
C:-susceptibility
D:-magnetic potential

Question 89:-While testing the field coil connections by compass method, the DC voltage to be applied to the field coil is
A:-10 to 20% of rated voltage
B:-the rated voltage
C:-60 to 70% of rated voltage
D:-200% of rated voltage

Question 90:-The relays which are capable of maintaining their contacts in the last assumed position after the power is cut off are
A:-latching relays
B:-thermal relays
C:-reed relays
D:-elctro-mechanical relays

Question 91:-In large motor generator sets, the AC motor used is usually
A:-squirrel cage type induction motor
B:-wound rotor type induction motor
C:-synchronous motor
D:-universal motor

Question 92:-A watt meter measures the
A:-Apparent power
B:-Active power
C:-Reactive power
D:-Power factor

Question 93:-A series resonant circuit is known as acceptor circuit, because its ______ will be maximum
A:-voltage
B:-current
C:-power factor
D:-frequency

Question 94:-With two watt meter method of 3 phase power measurement, if one watt meter gives negative indication, then, the power factor will be
A:-unity
B:-zero
C:-more than 0.5
D:-less than 0.5

Question 95:-A moving coil milliammeter having a resistance of 10 ohm gives full scale deflection, when a current of 5mA is passed through it. If the instrument to be used to measure a current up to 1A, then
A:-a resistance of 0.502 ohm must be connected in series with the ammeter
B:-a resistance of 0.502 ohm must be connected in series with the load
C:-a resistance of 0.502 ohm must be connected in parallel to the ammeter
D:-a resistance of 0.502 ohm mus be connected in parallel to the load

Question 96:-The instrument which give the value of quantity to be measured in terms of deflection and instrument constants are
A:-secondary instruments
B:-indicating instruments
C:-integrating instruments
D:-absolute instruments

Question 97:-A measuring instrument is enclosed inside an iron case. This is for protecting the measuring mechanism from
A:-heat
B:-magnetic flux
C:-static electricity
D:-hysteresis effect

Question 98:-The cell voltage of a Lithium cell is
A:-2.1 to 2.6V
B:-2.5 to 3.6V
C:-1.2 to 1.4 V
D:-1.5V

Question 99:-The illumination is directly proportional to the cosine of the angle made by the normal to the illuminated surface with the direction of the incident flux. This statement is associated with
A:-Macbeth’s law of illumination
B:-Bunsen’s law of illumination
C:-Lambert’s cosine law
D:-Plank’s law

Question 100:-In a drill, ______ helps to form the cutting edge.
A:-Land
B:-Shank
C:-Tang
D:-Flutes