EMI OBJECTIVE QUESTIONS
UNIT-I
1. A digital voltmeter has a readout range from 0 to 9,999 counts. Determine the resolution [01D01]
a.
1 mv
b.
10 mV
c.
1 μV
d.
100 mV
2. Which of the following is not a static characterstics? [01M01]
a.
Drift
b.
Dead zone
c.
Sensitivity
d.
Fiedlity
3. ______ is defined as the difference between the largest and smallest reading of instrument [01M02]
a.
Span
b.
Range
c.
Dead space
d.
Resolution
4. ____ refers to the degree of closeness or conformity to the true value of quantity under measurement
[01M03]
a.
Precision
b.
Accuracy
c.
Drift
d.
Resolution
5. ________ is defined as the nearness of the indicated value to the true value of the quantity being
measured [01S01]
a.
Accuracy
b.
Resolution
c.
Reproducibility
d.
Static error
6. ______ is defined as the ability of the instrument to reproduce a certain set of readings within a given
accuracy [01S02]
a.
Accuracy
b.
Precision
c.
Reproducibility
d.
Static error
7. ______ is defined as the largest change in input quantity for which there is not output of the
instrument [01S03]
a.
b.
c.
d.
Drift
Dead zone
Fiedlity
Accuracy
8. The smallest measurable input change is called _______ [01S04]
a.
Resolution
b.
Threshold
c.
Dead Zone
d.
Drift
9. The smallest measurable input is called _______ [01S05]
a.
Resolution
b.
Threshold
c.
Dead Zone
d.
Drift
10. A wheat stone bridge requires a change of 7 Ω in the unknown arm of the bridge to produce a change
in deflection of 3mm of the galvanometer sensitivity is _____ [02D01]
a.
3/7
b.
7/3
c.
9/49
d.
49/9
11. The voltage of a circuit is measured by a voltmeter having input impedance comparable with the
output impedence of the circuit there by causing error in voltage measurment. This error may be
called as [02D02]
a.
Gross error
b.
Random
c.
Error caused by misuse of instrument
d.
Error caused by loading effect
12. A meter reads 127.50V and the true value of voltage is 127.43
(i) static error ___________
(ii) static correction _______ [02M01]
a.
0.07V, 0.07V
b.
0.07V, -0.07V
c.
-0.07V, 0.07V
d.
-0.07V, 0.07V
13. Find the span for given range
Upper limit:55V
Lower Limit: 0V [02M02]
a.
55
b.
60
c.
45
d.
40
14. A Thermometer reads 95.450C and the static correction given in the correction curve is -0.080C. Then
the True value is ______ [02S01]
a.
b.
c.
d.
95.37
95.53
95.47
95.63
15. What types of errors are due to shortcomings of the instruments like detective (or) worn parts?
[02S02]
a.
Gross errors
b.
Systematic errors
c.
Random errors
d.
Environment errors
16. What type of errors is due to largely human errors like misreading of instruments? [02S03]
a.
Gross errors
b.
Systematic errors
c.
Random errors
d.
Environmental errors
17. Variance = [02S04]
a.
Standard deviation
b.
1/standard deviation
c.
1/(standard deviation)2
d.
(standard deviation)2
18. A 0-300V voltmeter has an error of ± 2% of full scale deflection. What would be the range of readings
if true voltages is 30V ? [03D01]
a.
24V-36V
b.
29.4V-30.6V
c.
20V to 40V
d.
30V-40V
19. ______ is defined as the degree to which the instrument indicates the changes in the measured
without dynamic error [03M01]
a.
Fiedlity
b.
Dynamic error
c.
Speed of response
d.
Settling time
20. ______ is the time for the instrument ot reach and stay within a specified tolerance band around its
final value [03M02]
a.
b.
c.
d.
e.
Fiedlity
Dynamic error
Speed of response
Settling time
Unit II
1.
The range of AF oscillators [06M02]
2.
a.
b.
c.
d.
In a series
a.
b.
c.
d.
10 kHz - 30 MHz
20 H3 to 20 kHz
dc - 5 MHz
1.5 MHz to 30 MHz
Type of ohmmeter, the zero adjustment should be done [06S01]
By changing the value of series resistance
By changing the value of shunt resistance connected across the meter movement
By changing both series as well as the shunt resistance
By changing the battery voltage
3.
4.
5.
A make break switch is provided to disconnect the battery when the meter is not in use in [06S02]
a.
Both series and shunt ohmmeters
b.
Only in series Type ohmmeters
c.
Only in shunt type ohmmeter
d.
For series Type of voltmeter
(i) The sensitivity of a DC voltmeter is an important factor when selecting a meter for a certain
voltage measurement
(ii) A low sensitivity meter may give correct readings when measuring voltages in low resistance
circuits [06S03]
a.
Both are True
b.
(i) is True, (ii) is false
c.
Both are false
d.
(i) is false, (ii) is True
The following general precautions should be observed when using a voltmeter
(i) Always be aware of loading effect
(ii) When using a multirange voltmeter, always use the highest voltage range and then decrease
the range until a good up scale reading is obtained [06S04]
6.
a.
b.
c.
d.
The pulse
Both are false
(i) is True, (ii) is false
Both are True
(ii) is True, (i) is false
Risetime is defind as the time taken by the pulse [06S05]
7.
a.
to go from 10% to 90% of its amplitude
b.
to go from 0% to 100% of its amplitude
c.
to go from 0% to 90% of its amplitude
d.
to go from 10% to 100% of its amplitude
In signal generator [07S01]
a.
b.
c.
8.
energy is created
energy is generated
energy is converted from a simple dc source into a.c energy at some specific
frequences
d. energy is consumed
Which of them is not a AF oscillators? [07S04]
9.
a. Beat frequency oscillator
b. Wein bridge oscillator
c. Phase shift oscillator
d. Tunnel diode oscillator
The simple sine wave generator consists of [07S05]
a. Only an oscillator
b. Only an attenuator
c. Oscillator, attenuator
d. Frequency divider, attenuator
10. The amplitude accuracy of sine wave generator depends on [07S06]
a. Only design of the attenuater
b. Only design of the oscillator
c. Only design of the frequency divider
d. Both the attenuator, oscillator
11. In the oscillatory circuit, the elements can be used to set the frequency of oscillator [08S01]
a. inductor, resistor
b. inductor, capacitor
c. capacitor, resistor
d. inductor, resistor
12. _______ is defined as the ratio of average value of the pulse over one cycle and the peak value
are inversely related to their time duration [08S02]
a.
b.
c.
Duty cycle
Complete cycle
Synchro cycle
d. Wave cycle
13. Expansion for B.F.O [08S03]
a. Beat frequency oscillator
b. Best frequency oscillator
c. Beat frequency osciloscope
d. Best frequency osciloscope
14. Which combination of the statemnts is applicable
(i) The most common outputs from the function generates is sine, square, Triangular waves
The frequency of these wave forms may be adjusted from a fraction of a hertz to several hundred
kilo Hertz [08S04]
a. (i), (ii) are correct
b. (i), (ii) are wrong
c. (i) correct, (ii)wrong
d. (i) wrong, (ii) correct
15. Output impedence of a laboratory quality pulse generator (Typical specification) [09D01]
a. 50 Ω
b. 100 Ω
c. 1KΩ
d. 5KΩ
16. Pulse width of a laboratory quality pulse generator (Typical specification) [09D02]
a.
b.
c.
d.
25n sec to 3 sec
4 sec to 10 sec
1 sec to 3 sec
7 sec to 10 sec
17. Determine frequency for pulse generator R=75 kΩ, C=0.01 μF, F=
a.
b.
c.
d.
18. Determine
[09M01]
924 Hz
724 Hz
824 Hz
1024 Hz
pulse width for pulse generator R=75 kΩ, C=0.01 μF, T=0.693 RC=? [09M02]
a. 0.173 ms
b. 0.173 ns
c. 0.173 s
d. 1.73 s
19. Compute duty cycle for given information pulse width=0.173, pulse period = 1.08; Duty cycle=?
[09M03]
a. 16%
b. 26%
c. 36%
d. 06%
20. A function generator is a versatile instrument that delivers a choice of different waveforms whose
frequencies are ________ [09S01]
a.
b.
c.
d.
fixed
variable over a small range
variable over a wide range
depends on wave form
Unit III
1.
For spectral display uses [14S02]
a.
b.
c.
d.
CRO
T.V
LCD
Digital display
2. The Heart of the oscilloscope [14S03]
a.
b.
c.
d.
3. It is not a
4.
a.
b.
c.
d.
Power supply Block
Vertical amplifier
Cathode ray Tube
Horizontal amplifier
part of CRT [14S04]
Vertical amplifier
Deflection plates
Electron gun
Fluorescent screen
How an AC bridge is used in amplifiers and oscillators ? [05D04]
a.
generate an additional amount of power
b.
provide a impedance matching
c.
provide a feed back
d.
path provide filtering
5. Expansion for B.F.O [08S03]
f.
g.
h.
i.
6.
Beat frequency oscillator
Best frequency oscillator
Beat frequency osciloscope
Best frequency osciloscope
Which combination of the statemnts is applicable
(i) The most common outputs from the function generates is sine, square, Triangular waves
The frequency of these wave forms may be adjusted from a fraction of a hertz to several
hundred kHZ
a. (i), (ii) are correct
b. (i), (ii) are wrong
c. (i) correct, (ii)wrong
d. (i) wrong, (ii) correct
7. Output impedence of a laboratory quality pulse generator (Typical specification) [09D01]
a. 50 Ω
b. 100 Ω
c. 1KΩ
d. 5KΩ
8. Pulse width of a laboratory quality pulse generator (Typical specification) [09D02]
a.
b.
c.
d.
25n sec to 3 sec
4 sec to 10 sec
1 sec to 3 sec
7 sec to 10 sec
9. Determine frequency for pulse generator R=75 kΩ, C=0.01 μF, F=
a.
b.
c.
d.
924 Hz
724 Hz
824 Hz
1024 Hz
[09M01]
10.
Determine pulse width for pulse generator R=75 kΩ, C=0.01 μF, T=0.693 RC=? [09M02]
a. 0.173 ms
b. 0.173 ns
c. 0.173 s
d. 1.73 s
11. Compute duty cycle for given information pulse width=0.173, pulse period = 1.08; Duty cycle=?
[09M03]
a. 16%
b. 26%
c. 36%
d. 06%
12. A function generator is a versatile instrument that delivers a choice of different waveforms whose
frequencies are ________ [09S01]
a.
b.
c.
d.
fixed
variable over a small range
variable over a wide range
depends on wave form
13.
a.
b.
c.
d.
The most basic pulse generator [09S03]
astable multivibrator
monostable multivibrator
schmitt trigger
frequency control
14. The frequency of pulse is 924Hz. Compute time periood T=? [09S04]
a. 0.08ms
b. 1.08ms
c. 2.08 ms
d. 3.08ms
15. Semiconductor noise diode given an output frequency in the band [10D01]
a. 1 Hz to 100Hz
b. 100 Hz to 10n KHz
c. 50 KHz to 200 KHz
d. 200 KHz to 1 MHz
16. In sweep generator, the time base is usually adjustable to give output sweep times in the
range from [10M01]
a.
b.
c.
d.
17. In
less than 10ms
10m to greter than 100s
1 μs to 10μs
10 μs to 100μs
swept frequency generator, The time base is frequently a [10M02]
a. sine wave
b. sine wave(or)pulse
c. Trangular (or) sawtooth
d. Trangular or sine wave
18. (i) The two modes are used to set the swept frequency range (1) the start-stop, (2) Δ f
mode
(ii) The stop and start frequency are set from the front panel [10M03]
a.
b.
c.
d.
(i), (ii) are True
(i), is True, (ii) is false
(i) (ii) are false
(i) is false (ii) is true
19. An stable multivibrator uss a resistance of 100 kΩ and capacitance 0.01 μF. The frequency of
square wave generated by it is [10S01]
a.
b.
c.
d.
20. A
a.
b.
c.
d.
924 Hz
0
593Hz
693 Hz
110 Hz
random noise generator produces a single [10S03]
Whose amplitude varies randomly
Which has no periodic frequency
Has an unpredictable power specturn
Whose amplitude constant
UNIT-IV
1. In a transducer, the experimentally obtained transfer function is different from the
Theoretical transfer function, the errors result from this difference are called ----a. zero error
b. Hysteresis error
c. sensitivity error
d. non-conformity errors
2. The lower limit of useful working range of a transducer is determined by---a. minimum useful input level
b. constant current source
c. transducer error and noise
d. constant current source
3. In transducer, the observed output deviates from the correct value by a constant factor
the-resulting error is called --a. zero error
b. Hysteresis error
c. sensitivity error
d. non-conformity errors
4. Passive transducers derive the power required for transduction from---a. a constant power supply
b. an auxiliary power source
c. physical quantity being measured
d. internal power supply
5. Active transducers derive the power required for transduction from ----a. a constant power supply
b. an auxiliary power source
c. physical quantity being measured
d. internal power supply
6. Transducer converts ---a. analog signal into digital signal
b. digital signal into analog signal
c. one form of energy into other form of energy
d. mechanical displacement into mechanical energy
7. An inverse transducer converts ---a. analog signal into digital signal
b. digital signal into analog signal
c. an electrical energy to any other form of energy
d. an optical signal to any other form of energy
8. one of the following can act as an inverse transducer ---a. strip chart recorder
b. strain gauge
c. LVDT
d. piezo electric crystals
9. One of the following is an active transducer----a. strain gauge
b. photovoltaic cell
c. photo emissive cell
d. selsyn
10. In a resistance potentiometer high value of resistance leads to ----a. high value of sensitivity
b. low value of error
c. low value of non-linearity
d. high value of selectivity
11. What is the order of minimum displacement that can be measured with capacitive
transducers?
a. 1cm
b. 1 mm
c. 1μm
d. 1 m
12. Capacitive transducers using the principle of change of capacitance with change of
dielectric are normally used for measurement of ---a. displacement
b. pressure
c. force
d. liquid levels
13. Two inductive transducers working on the principle of change of self inductance L, are
Connected in a push pull arrangement. If the change of inductance of transducers is ΔL the change of
inductance exhibited at the output terminals is---a.
ΔL
b. ΔL
c. 2ΔL
d. 2ΔL
14. The dynamic characteristics of capacitive transducers are similar to those of ---a. low pass filters
b. high pass filters
c. notch filters
d. band stop filters
15. A capacitive transducer working on the principle of change of capacitance with change of
displacement exhibits non linear characteristics. The response of these transducers can be
made linear by using --a. non -magnetic material
b. a solid ferror-electric material
c. nickel-iron hydrogen annealed material
d. differential arrangement or use of an op AMP
16. The sensitivity of the capacitive transducer can be increased by making---a. the distance between the plates extremely small
b. the distance between the plates extremely large
c. the electric field in the air gap exceeds the break down voltage
d. dielectric constant low
17. Air cored inductive transducers are suitable for---a. low frequencies
b. high frequencies
c. same frequencies as iron cored transducers d. both low and high frequencies
18. The size of air cored inductive transducers as compared with the iron cored transducers
a. smaller
b. higher
c. same
d. exactly halved
19. Capacitive transducers are normally used for---a. dynamic measurements
b. static measurements
c. transient measurements
d. gauge measurement
20. Capacitive transducers can be used for measurement of liquid level. The principle of
Operation used in this case is --a. change of capacitance
b. change of area of plates
c. change of dielectric strength
d. change of distance between plates
Unit V
1. The measured value of power in AC circuits is equal to ----a. middle power of one cycle
b. average power over a cycle
c. instantaneous power
d. power
2. A bridge circuit works at a frequency of 2 KHz. The following can be used as detectors for
detection of null conditions in the bridge
a. headphones and vibration galvanometer
b. headphones and tunable amplifiers
c. vibration galvanometers and tunable amplifier
d. tunable amplifiers and vibration galvanometers
3. Wagner's earth devices are used in ac bridge circuits for
a. eliminating the effect of earth capacitances-----b. eliminating the effect of inter-component capacitances
c. shielding the bridge elements
d. eliminating the effect of stray electrostatic fields
4. For the bridge, Z1=200<300 Z2 = 150<00 and Z3=250<-400. In order that the bridge be
Balanced Z4 should be ------a. 120<600
b. 187.5<-700
c. 333.3<100
d. 100<-400
5. How an AC bridge is used in amplifiers and oscillators ?
a. generate an additional amount of power
b. provide a impedance matching
c. provide a feed back
d. path provide filtering
6. The equation under balance conditions for a bridge are: R1=R2R3/R4 and L1=R2R3/C4 whereR1and L1 are
respectively unknown resistance and inductance. In order to achieve convergingbalance---------a. R1 and C4 should be chosen as variable
b. R2 and C4 should be chosen as variable
c. R1 and R2 should be chosen as variable
d. R4 and C4 should be chosen as variable
7. For the measurement of inductance and capacitance using AC bridge, the oscillator have
a. variable frequency and high power of about kw
b. variable frequency and very high power of about kw
c. fixed frequency and low power of mw
d. fixed frequency and output of about 1 w
8. In order to satisfy both conditions for balance and for convenience of manipulation, the
Bridge must contain-----a. a head phone and an oscillator
b. vibration galvanometer and head phones
c. two variable elements in its configuration
d. four fixed elements in its configuration
9. In order that the bridge to be balanced ---a. Z1Z4 =Z2Z3 and <θ1+<θ4 = <θ2+<θ3
b. Z1/Z4 =Z2 /Z3 and <θ1+<θ4 =<θ2+<θ3
c. Z1Z4 =Z2Z3 and <θ1 <θ4 = <θ2<θ3
d. Z1Z4 =Z2Z3 and <θ1 -< θ4 = <θ2 -<θ3
10. For the bridge abcd, arm ab consists of resistance in series with an inductance, arm bc and
Ad consist of pure resistance. In order to achieve balance are cd should consist of------a. pure resistance
b. inductance in series with capacitance
c. a variable resistance in series or parallel with a variable capacitance
d. a pure resistance in parallel with a inductance
11. An AC bridge in its basic form, consists of -----a. four arms and shielding the bridge element
b. four arms, a source of excitation and balance detector
c. Wagner's earth device and four arms
d. four arms and source of excitation
12. A suspension type galvanometer having a sensitivity 0.5μA per scale division is used to
Measure-----a. inductance
b. dc resistance
c. ac resistance
d. frequency
13. In a voltage sensitive Wheatstone, having a resistance, R, the resistance of one of the arms
is changed to R+ΔR where ΔR < < R. The Wheatstone bridge is supplied with an input voltage of ei.The output
voltage on account of unbalance is-----a.1
b.2
c.3
d.None
14. The advantage of Hay's bridge over Maxwell s inductance-capacitance bridge is ----a. it can be used for measurement of inductance of low Q coils
b. it can be used for measurement of inductance of high Q coils
c. it can be used for measurement of inductance of low and medium Q coils
d. its equations for balance do not contain any frequency term
15. The expression for unknown inductance of high Q coils using Hay's bridge is ---a. L2=R2R3/C4
b. L3=R2R3/C4
c. L1=R2R3/C4
d. L1=R2R3C4
16. In the Wein's bridge, to balance the harmonics ----a. a vibration galvanometer is used
b. high voltage supply is used
c. a square wave is used as input
d. a filter is connected in series with the null detector
17. Frequency can be measured by using ---a. Maxwell's bridge
b. Hay's bridge
c. Schering bridge
d. Wien's bridge
18. The following bridge is used in harmonic distortion analyzer ----a. Wein's bridge
b. Campbell's bridge
c. Maxwell's bridge
d. Hay's bridge
19. Why the sinusoidal voltage is required to balance the Wein s Bridge?
a. it required a high voltage as supply
b. because of its frequency sensitivity
c. harmonics will sometimes produce masking
d. a filter is used to balance the bridge
20. The expression for frequency using Weins bridge is ---a.F=1/2∏R
b. F=1/2RC
c. F=1/2∏RC
d. F=2∏RC