Solved preview paper 3(101-145)

Q.101. One of the main application of Magneto-resistor
a.) Rectification
b.) Field compensation
c.) Voltage regulation✔
d.) Power amplification

Q.102. Input impedance of an ideal Op- Amp is
a.) Finite
b.) Zero
c.) Infinite✔
d.) Unity

Q.103. For the binary number 1110 1000 the equivalent hexadecimal number is
a.) F9
b.) F8
c.) E9
d.) E8✔

Q.104. In 2's complement from , -2  is
a.) 1011
b.) 1110✔
c.) 1100
d.) 1010

Q.105. The most commonly used logic family is
a.) ECL
b.) TTL
c.) CMOS✔
d.) PMOS

Q.106. ALE stand for
a.) Address latch enable✔
b.) Accumulator latch enter
c.) Address latch enter
d.) None of the above

Q.107. The number of gates in a SCR is
a.) 2✔
b.) 3
c.) 4
d.) 6

Q.108. Relaxation oscillator uses
a.) Tunnel diode
b.) UJT✔
c.) Both tunnel diode and UJT
d.) PIN

Q.109. In overhead lines we generally use
a.) Copper condenser
b.) ACSR conductor✔
c.) Aluminium conductor
d.) None of the above

Q.110. The electric power can be transmitted by
a.) Overhead system
b.) Underground system
c.) Either A or B✔
d.) None of the above

Q.111. Which variety of copper has the best conductivity
a.) Pure annealed copper✔
b.) Hard drawn copper
c.) Induction hardened copper
d.) Copper containing silicon

Q.112. Basic ceramic material is
a.) Limestone
b.) Clay✔
c.) Cellulose
d.) Sand

Q.113. Which of the following insulating material has the highest safe working temperature
a.) Polythene
b.) Bakelite
c.) Mica✔
d.) Empire cloth

Q.114. Thermocouple works on
a.) Thomson effect
b.) Seebeck effect✔
c.) Peltier effect
d.) Joule affect

Q.115. In a commutator
a.) Copper is harder than Mica✔
b.) Mica and copper are equally harder
c.) Mica is harder than copper
d.) None of the above

Q.116. An electric boiler draws 12 A  at 115 V for a period of 6 hours. If the electrical energy costs 30 paisa per kWh,  then cost of boiler operation in ₹ is
a.) 8.284
b.) 3.482
c.) 2.484✔
d.) 1.684

Q.117. A hundred watt 250 volt bulb is put in series with a 40 watt , 250 volt bulb across 500 volt supply. That total resistance offered by both the bulbs in the circuit in home is
a.) 218.75
b.) 318.75
c.) 3187.5
d.) 2187.5✔

Q.118. When a source is delivering maximum power to the load the efficiency will be
a.) Maximum
b.) Below 50%
c.) Above 50%
d.) 50%✔

Q.119. A 12 volt lead acid battery used in a car contains
a.) 10 cell connected in series
b.) 10 cell connected in parallel
c.) 6 cell connected in parallel
d.) 6 cell connected in series✔

Q.120. The force per metre length between two conductors 0.05 m apart carrying 1000 A and 5000 A is
a.) 20 N✔
b.) 5 N
c.) 50 N
d.) 25 N

Q.121. What will be the current passing through the ring shaped air cored cail when the number of turns is 800 and ampere-turn are 3200
a.) 0.25
b.) 2.5
c.) 4.0✔
d.) 0.4

Q.122. In RLC series circuit at resonance frequency the voltage across the resistance is
a.) Much lower than applied voltage
b) Equal to the applied voltage✔
c.) Much higher then applied voltage
d.)Function of the value of inductance

Q.123. An alternating voltage of (160+j120)V is applied to a circuit and the current in the circuit is given by (6+j8)A . The value of the circuit impedance in ohms is given by
a.)19.2-j5.6✔
b.)19.2+j5.6
c.)166+j128
d.)154-j112

Q.124. A resistor R in series with a capacitor C is connected to a 50 Hz , 240 volt supply. The register observe 300 watt 100 volt . The voltage across the capacitor is
a.) 118.17 V
b.) 318.17 V
c.) 218.17 V✔
d.) 418.17 V

Q.125. An alternating current is represented by i=70.7 sin 520t . Then the value of frequency is Hz is
a.) 73
b.) 93
c.) 53
d.) 83✔

Q.126. A battery of 50 cells in series is charged through a resistance of 4 ohm from a 230 volt supply. If the terminal voltage per cell is 2 volt and 2.7 volt respectively at the beginning and at the end of the charge. The charging current at the beginning is given by
a.) 22.5 A
b.) 12.5 A
c.) 32.5 A✔
d.) 18.5 A

Q.127. The power in the wind Pw through a given cross sectional area for a uniform wind velocity V is
a.) Pw=KV^3
b.) Pw=KV^2
c.) Pw=KV✔
d.) Pw=KV^4

Q.128. Which of the following statement is correct ?
a.) Arc in a circuit breaker is interrupted at Maximum current
b.) Arc in a circuit breaker is interrupted at maximum voltage
c.) Arc in a circuit breaker is interrupted at zero current✔
d.) Arc in a circuit breaker is interrupted at minimum voltage

Q.129. Which of the following circuit breaker has high reliability and minimum maintenance
a.) Oil circuit breaker
b.) Airblast circuit breaker
c.) Sf6 circuit breaker
d.) Vacuum circuit breaker✔

Q.130. The differential relaying system respond to
a.) Internal fault✔
b.) External fault
c.) Overvoltage fault
d.) Under current fault

Q.131. To protect the power transformer (Delta star)against internal faults the current transformer will have
a.) Delta - delta connections
b.) Delta - star connections
c.) Star - star connections
d.) Star - delta connections✔

Q.132. For a 400 kV line the spacing between phase conductors is around
a.) 8 m✔
b.) 11 m
c.) 14 m
d.) 17 m

Q.133. Bundled conductors are used to
a.) Reduce inductis of the line
b.) Reduce both inductance and capacitance
c.) Reduce Corona loss
d.) Reduce Corona loss and the line inductance✔

Q.134. The power factor of a system on a 460 volt 3 phase 60 Hz, in which the emitter indicate 10 volt and Watt metre reads 62 kW will be
a.) 0.95
b.) 0.78✔
c.) 0.85
d.) 0.72

Q.135. Which of the following protects the underground cables against mechanical injury
a.) Bedding
b.) Sheath
c.) Armouring✔
d.) None of these

Q.136. The thermal efficiency of a steam power station is
a.) 18%-20%
b.) 25%-30%✔
c.) 40%-50%
d.) 15%-20%

Q.137. Which of the following is not a secondary source of energy ?
a.) Solar power station✔
b.) Diesel power station
c.) Nuclear power station
d.) Thermal power station

Q.138. The synchronous speed of the revolving field depends upon
a) number of poles
b) supply frequency
c) flux
d) a and b are correct✔

Q.139. The frequency of induced emf in the rotor circuit is
a) maximum at stand still✔
b) zero at stand still
c) maximum at synchronous speed
d) none of these

Q.140. If one of the 3-phases of a 3-phase induction motor is disconnected while running at light load, it will
a) stop running
b) continue to run at same speed✔
c) run at low speed
d) run at high speed

Q.141. If the rotor terminals of a 3-phase slip ring induction motor are not short-circuited and the supply is given to the stator , the motor will
a) not start✔
b) start running
c) run at high speed
d) run at low speed

Q.142. Eddy current power loss in a magnetic material can be expressed as
a.)Pe=ke Bm^2t^2f^2 V watt✔
b.)Pe=ke Bm^2tf^2 V watt
c.)Pe=ke Bm t^2 f V watt
d.)Pe=ke Bm^2t^2f^2 V^2 watt

Q.143. In transistor with normal bias, the emitter Junction
a.) Has high resistance
b.) Reverse biased
c.) Has low resistance✔
d.) None

Q.144. Power factor of incandescent lamp is
a.) Zero
b.) Unity✔
c.) 0.8 legging
d ) 0.8 leading

Q.145. The colour of sodium vapour discharge lamp is
a.) Pink
b.) Red
c.) Bluish
d.) Yellow✔