101. The simultaneous applications of signals x (t) and y (t) to the horizontal and vertical planes respectively, of an oscilloscope, produce a vertical figure of 8 displays. If P and Q are constants and x(t) = P sin (4t + 30), then y(t) is equal to _________
A. Q sin (4t – 30)
B. Q sin (2t + 15)
C. Q sin (8t + 60)
D. Q sin (4t + 30)
102. A resistor of 10 kΩ with a tolerance of 5% is connected in parallel with 5 kΩ resistors of 10% tolerance. The tolerance limit is _______
A. 9%
B. 12.4%
C. 8.33%
D. 7.87%
103. A 200/1 Current Transformer (CT) is wound with 400 turns on the secondary on a toroidal core. When it carries a current of 180 A on the primary, the ratio is found to be − 0.5%. If the number of secondary turns is reduced by 1, the new ratio error (in %) will be?
A. 0.0
B. − 0.5
C. − 1.0
D. − 2.0
104. In the Two wattmeter method of measuring power in a balanced three-phase circuit, one wattmeter shows zero and the other positive maximum. The load power factor is ___________
A. 0
B. 0.5
C. 0.866
D. 1.0
105. The meter constant of a single-phase, 230 V induction watt-meter is 600 rev/kW − h. The speed of the meter disc for a current of 15 A at 0.8 power factor lagging will be?
A. 30.3 rpm
B. 25.02 rpm
C. 27.6 rpm
D. 33.1 rpm
106. In the figure given below, a 220 V 50 Hz supplies a 3 − phase balanced source. The pressure Coil (PC. and Current Coil (CC. of a wattmeter are connected to the load as shown. The wattmeter reading is _________
A. Zero
B. 1600 W
C. 242 W
D. 400 W
107. In the Owen’s bridge shown in below figure, Z1 = 200∠60°, Z2 = 400∠ − 90°, Z3 = 300∠0°, Z4 = 400∠30°. Then,
A. Bridge is balanced with given impedance values
B. Bridge can be balanced, if Z4 = 600∠60°
C. Bridge can be balanced, if Z3 = 400∠0°
D. Bridge cannot be balanced with the given configuration
108. In Maxwell’s capacitance bridge for calculating unknown inductance, the various values at balance are, R1 = 300 Ω, R2 = 700 Ω, R3 = 1500 Ω, C4 = 0.8 μF. The values of R1, L1 and Q factor, if the frequency is 1100 Hz are _________
A. 240 Ω, 0.12 H, 3.14
B. 140 Ω, 0.168 H, 8.29
C. 140 Ω, 0.12 H, 5.92
D. 240 Ω, 0.36 H, 8.29
109. In the figure below, the values of the resistance R1 and inductance L1 of a coil are to be calculated after the bridge is balanced. The values are _________________
A. 375 Ω and 75 mH
B. 75 Ω and 150 mH
C. 37.5 Ω and 75 mH
D. 75 Ω and 75 mH
110. The four arms of an AC bridge network are as follows:
Arm AB: unknown impedance
Arm BC: standard capacitor C2 of 1000pf
Arm CD: a non-inductive resistance of R of 100 Ω in parallel to a capacitor of 0.01 μF
Arm DA: a non-inductive resistance of 1000 Ω
The supply frequency is 50 Hz and connected across terminals B and D. If the bridge is balanced with the above value, determine the value of unknown Impedance.
A. 10 kΩ
B. 100 kΩ
C. 250 kΩ
D. 20 kΩ