# Single Phase & Half-Wave MCQ Questions & Answers

Single Phase & Half-Wave MCQs : This section focuses on the "Single Phase & Half-Wave". These Multiple Choice Questions (MCQs) should be practiced to improve the Single Phase & Half-Wave skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

70 V rated 6 SCRs are connected in series. The operation voltage of the string is 130. Calculate the De-rating factor.

A. 0.7
B. 0.73
C. 0.78
D. 0.74

Question 2

A step-down chopper has input voltage .1 V and output voltage .01 V. Calculate the value of the duty cycle.

A. 0.1
B. 0.2
C. 0.3
D. 0.5

Question 3

Calculate the circuit turn-off time for Half-wave controlled rectifier for a ?=5 rad/sec for resistive load.

A. .62 sec
B. .42 sec
C. .58 sec
D. .64 sec

Question 4

Calculate the conduction angle in purely inductive load if the firing angle is 165°.

A. 78°
B. 55°
C. 30°
D. 19°

Question 5

Calculate the De-rating factor if the string efficiency is 98%.

A. 0.04
B. 0.02
C. 0.05
D. 0.03

Question 6

Calculate the extinction angle in purely inductive load if the firing angle is 13°.

A. 328°
B. 347°
C. 349°
D. 315°

Question 7

Calculate the I0 avg for Single-phase Half Wave rectifier for R-L load using the data: Vm=56 V, ?=15°, ?=30°, R=2 ?.

A. .56 A
B. .44 A
C. .26 A
D. .89 A

Question 8

Calculate the I0 r.m.s for Single-phase Half Wave rectifier for R-L load (Highly inductive) using the data: Vm=110 V, ?=16°, ?=31°, R=1 ?.

A. 4.56 A
B. 1.82 A
C. 4.81 A
D. 9.15 A

Question 9

Calculate the output frequency for the six-pulse converter if the supply frequency is 10 Hz.

A. 40 Hz
B. 30 Hz
C. 60 Hz
D. 80 Hz

Question 10

Calculate the output voltage of the Buck converter if the supply voltage is 13 V and duty cycle value is .16.

A. 2.08 V
B. 2.24 V
C. 2.58 V
D. 2.54 V

Question 11

Calculate the PIV for the Full-wave bridge rectifier if the peak value of the supply voltage is 230.

A. 324.4 V
B. 325.2 V
C. 524.4 V
D. 626.8 V

Question 12

Calculate the pulse number if the supply frequency is 2? and the output frequency is ?÷6.

A. 4
B. 12
C. 16
D. 8

Question 13

Calculate the string efficiency if the de-rating factor is .429.

A. 48.1 %
B. 57.1 %
C. 47.8 %
D. 46.5 %

Question 14

Calculate the string efficiency if the de-rating factor is .50.

A. 28 %
B. 42 %
C. 80 %
D. 50 %

Question 15

Calculate the V0 avg for Single-phase Half Wave rectifier for R-L load using the data: Vm=24 V, ?=30°, ?=60°.

A. 1.39 V
B. 8.45 V
C. 4.55 V
D. 1.48 V

Question 16

Calculate the value of the conduction angle for diode for R-L load with a freewheeling diode if the value of ? is 45°. (Continous conduction mode)

A. 220°
B. 225°
C. 230°
D. 280°

Question 17

Calculate the value of the conduction angle for diode for R-L load with a freewheeling diode if the value of ? is 226°. (Discontinuous conduction mode)

A. 40°
B. 45°
C. 50°
D. 46°

Question 18

Calculate the value of the conduction angle for R-L load if the value of ? and ? are 19° and 29°.

A. 10°
B. 70°
C. 30°
D. 80°

Question 19

Calculate the value of the conduction angle for R-L load if the value of ? and ? are 56° and 18°.

A. 48°
B. 38°
C. 57°
D. 15°

Question 20

Calculate the value of the conduction angle for SCR for R-L load with a freewheeling diode if the value of ? and ? are 65° and 12°.

A. 168°
B. 170°
C. 130°
D. 180°

Question 21

Calculate the value of the fundamental displacement factor for 1-? Full wave bridge rectifier if the firing ?=17°.

A. 0.98
B. 0.19
C. 0.56
D. 0.95

Question 22

Calculate the value of the fundamental displacement factor for 1-? Full wave semi-converter if the firing angle value is 0o.

A. 1
B. 0.8
C. 0.4
D. 0.2

Question 23

Calculate the value of the fundamental displacement factor for 1-? Full wave semi-converter if the firing angle value is 95o.

A. 0.6
B. 0.68
C. 0.62
D. 0.67

Question 24

Calculate the value of the Input power factor using the data: Fundamental displacement factor=.96, Distortion factor=.97.

A. 0.93
B. 0.84
C. 0.48
D. 0.89

Question 25

Calculate the voltage across the freewheeling diode when the output voltage is 24 V.

A. -15 V
B. -24 V
C. 28 V
D. 39 V

Question 26

d(v)÷d(t) is more reliable for SCR triggering.

A. True
B. False

Question 27

Displacement factor depends upon the shape of the waveform.

A. True
B. False

Question 28

For highly inductive load current remains continuous.

A. True
B. False

Question 29

Full form of ADC is ___________

A. Analog to Digital converter
B. Discrete to Analog converter
C. Analog to Digital converter
D. Discrete to Avalanche converter

Question 30

Full form of DAC is ___________

A. Digital to Analog converter
B. Discrete to Analog converter
C. Digital to AC converter
D. Discrete to Avalanche converter

Question 31

Full form of PIV.

A. Peak inverse voltage
B. Peak insert voltage
C. Paas Inverse volatile
D. Peak insert volatile

Question 32

In Half-wave controlled rectifier calculate the average value of the current for 2.5 ? resistive load if the supply is sin(5.2t) and firing angle is 26°.

A. 0.8 V
B. 0.15 V
C. 0.12 V
D. 0.21 V

Question 33

In Half-wave controlled rectifier calculate the average value of the voltage if the supply is 13sin(25t) and firing angle is 13°.

A. 4.08 V
B. 4.15 V
C. 3.46 V
D. 5.48 V

Question 34

In Half-wave uncontrolled rectifier calculate the average value of the current for 3 ? resistive load if the supply is 34sin(11t).

A. 3.6 A
B. 2.6 A
C. 2.5 A
D. 3.1 A

Question 35

In Half-wave uncontrolled rectifier calculate the average value of the voltage if the supply is 3sin(5t).

A. .95 V
B. .92 V
C. .93 V
D. .94 V

Question 36

In Half-wave uncontrolled rectifier calculate the power dissipation across the 8 ? resistor if the supply is 29sin(22t).

A. 26.2 W
B. 24.2 W
C. 26.1 W
D. 29.1 W

Question 37

In Half-wave uncontrolled rectifier calculate the r.m.s value of the voltage if the supply is 89sin(41t).

A. 91.5 V
B. 44.5 V
C. 25.1 V
D. 15.1 V

Question 38

In single phase RLE load, calculate the angle at which conduction starts using the data: (Vs)=14sin(?t), f=50 Hz, E=10 V.

A. 45.58°
B. 46.26°
C. 47.26°
D. 49.56°

Question 39

In single phase RLE load, calculate the Peak inverse voltage using the data: (Vs)r.m.s=89 V, f=50 Hz, E=440 V.

A. 521.2 V
B. 527.8 V
C. 597 V
D. 529 V

Question 40

In single phase RLE load, calculate the voltage across the thyristor when current decays to zero using the data: (Vs)r.m.s=340 V, f=50 Hz, R=2 ?, E=150 V, ?=160°.

A. 45.89 V
B. 74.45 V
C. 54.85 V
D. 84.48 V

Question 41

A. True
B. False

Question 42

The conduction period of diode in Half-wave uncontrolled rectifier for resistive load is ______________

A. ?
B. 2?
C. 3?
D. 4?

Question 43

Volt-sec balance method is based on the principle of the energy of conservation.

A. True
B. False

Question 44

Which one of the following load is suitable for lagging power factor load in Single phase Half-bridge inverter?

B. R-L-C overdamped
C. R-L-C underdamped

Question 45

Which one of the following load is suitable for leading power factor load in Single phase Half-bridge inverter?

B. R-L-C overdamped
C. R-L-C underdamped

Question 46

Calculate the circuit turn-off time for Half-wave controlled rectifier for a ω=5 rad/sec for resistive load.

A. .62 sec
B. .42 sec
C. .58 sec
D. .64 sec

Question 47

Calculate the I0 avg for Single-phase Half Wave rectifier for R-L load using the data: Vm=56 V, ∝=15°, β=30°, R=2 Ω.

A. .56 A
B. .44 A
C. .26 A
D. .89 A

Question 48

Calculate the I0 r.m.s for Single-phase Half Wave rectifier for R-L load (Highly inductive) using the data: Vm=110 V, ∝=16°, β=31°, R=1 Ω.

A. 4.56 A
B. 1.82 A
C. 4.81 A
D. 9.15 A

Question 49

Calculate the pulse number if the supply frequency is 2π and the output frequency is π÷6.

A. 4
B. 12
C. 16
D. 8

Question 50

Calculate the string efficiency if the de-rating factor is .429.

A. 48.10%
B. 57.10%
C. 47.80%
D. 46.50%

Question 51

Calculate the string efficiency if the de-rating factor is .50.

A. 28%
B. 42%
C. 80%
D. 50%

Question 52

Calculate the V0 avg for Single-phase Half Wave rectifier for R-L load using the data: Vm=24 V, ∝=30°, β=60°.

A. 1.39 V
B. 8.45 V
C. 4.55 V
D. 1.48 V

Question 53

Calculate the value of the conduction angle for diode for R-L load with a freewheeling diode if the value of α is 45°. (Continous conduction mode)

A. 220°
B. 225°
C. 230°
D. 280°

Question 54

Calculate the value of the conduction angle for diode for R-L load with a freewheeling diode if the value of β is 226°. (Discontinuous conduction mode)

A. 40°
B. 45°
C. 50°
D. 46°

Question 55

Calculate the value of the conduction angle for R-L load if the value of β and α are 19° and 29°.

A. 10°
B. 70°
C. 30°
D. 80°

Question 56

Calculate the value of the conduction angle for R-L load if the value of β and α are 56° and 18°.

A. 48°
B. 38°
C. 57°
D. 15°

Question 57

Calculate the value of the conduction angle for SCR for R-L load with a freewheeling diode if the value of β and α are 65° and 12°.

A. 168°
B. 170°
C. 130°
D. 180°

Question 58

Calculate the value of the fundamental displacement factor for 1-Φ Full wave bridge rectifier if the firing α=17°.

A. 0.98
B. 0.19
C. 0.56
D. 0.95

Question 59

Calculate the value of the fundamental displacement factor for 1-φ Full wave semi-converter if the firing angle value is 0o.

A. 1
B. 0.8
C. 0.4
D. 0.2

Question 60

Calculate the value of the fundamental displacement factor for 1-Φ Full wave semi-converter if the firing angle value is 95o.

A. 0.6
B. 0.68
C. 0.62
D. 0.67

Question 61

In Half-wave controlled rectifier calculate the average value of the current for 2.5 Ω resistive load if the supply is sin(5.2t) and firing angle is 26°.

A. 0.8 V
B. 0.15 V
C. 0.12 V
D. 0.21 V

Question 62

In Half-wave uncontrolled rectifier calculate the average value of the current for 3 Ω resistive load if the supply is 34sin(11t).

A. 3.6 A
B. 2.6 A
C. 2.5 A
D. 3.1 A

Question 63

In Half-wave uncontrolled rectifier calculate the power dissipation across the 8 Ω resistor if the supply is 29sin(22t).

A. 26.2 W
B. 24.2 W
C. 26.1 W
D. 29.1 W

Question 64

In single phase RLE load, calculate the angle at which conduction starts using the data: (Vs)=14sin(Ωt), f=50 Hz, E=10 V.

A. 45.58°
B. 46.26°
C. 47.26°
D. 49.56°

Question 65

In single phase RLE load, calculate the voltage across the thyristor when current decays to zero using the data: (Vs)r.m.s=340 V, f=50 Hz, R=2 Ω, E=150 V, β=160°.

A. 45.89 V
B. 74.45 V
C. 54.85 V
D. 84.48 V

Question 66

The conduction period of diode in Half-wave uncontrolled rectifier for resistive load is ______________

A. π
B. 2π
C. 3π
D. 4π