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Multiple choice question for engineering

Set 1

1. Electrodes to measure EEG are placed on ________
a) forehead
b) scalp
c) cheek
d) ears

View Answer

Answer: b [Reason:] Electrode to measure EEG are placed on the scalp. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.

2. According to the international 10/20 system to measure EEG, even number denotes which side of the brain?
a) left
b) top
c) bottom
d) right

View Answer

Answer: d [Reason:] The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Even number denotes the right side of the head.

3. Letter F in the EEG electrode placement system denotes?
a) front
b) face
c) frontal lobe
d) fast

View Answer

Answer: c [Reason:] F denotes frontal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.

4. Normal EEG frequency range is _______
a) 50-500Hz
b) 0.5-50HZ
c) 0.05-5Hz
d) 1-200Hz

View Answer

Answer: b [Reason:] The frequency varies greatly with different behavioral states. The normal EEG frequency content ranges from 0.5 to 50Hz. The nature of the wave varies over the different parts of the scalp.

5. The letter T in the EEG electrode placement system denotes?
a) temporal lope
b) temper lobe
c) trace
d) timpanic

View Answer

Answer: a [Reason:] T denotes temporal lobe of the head. The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number.

6. According to the international 10/20 system to measure EEG, odd number denotes which side of the brain?
a) left
b) right
c) top
d) front

View Answer

Answer: a [Reason:] The position of each electrode is specified using the International 10/20 system. Each electrode site is labeled with a letter and a number. Odd number denotes the left side of the head.

7. The delta wave in EEG ranges from ___________
a) 0.5-4Hz
b) 4-8Hz
c) 8-13Hz
d) 13-22Hz

View Answer

Answer: a [Reason:] The delta wave in EEG ranges from 0.5-4Hz. The theta wave in EEG ranges from 4-8Hz. The alpha wave in EEG ranges from 8-13Hz and beta from 13-22Hz.

8. Disturbance in the EEG pattern resulting from the external stimuli is called ________
a) provoked response
b) ckoored response
c) evoked response
d) impulse response

View Answer

Answer: b [Reason:] Disturbance in the EEG pattern resulting from the external stimuli is called evoked response. The stimuli could be a flash light or a click of sound. The stimuli can be repeated and the EEG waveform can be observed to find the activities occurring because of the stimuli.

9. The peak to peak amplitude of the waves that can be picked from the scalp is______________
a) 100mV
b) 100V
c) 100uV
d) 10mV

View Answer

Answer: c [Reason:] The EEG signal can be picked up with electrodes either from the scalp or directly from the cerebral cortex. The peak to peak amplitude of the waves that can be picked up from the scalp is normally 100uV. The frequency varies greatly with different behavioral states.

10. Which rhythm is the principal component of the EEG that indicates the alertness of the brain?
a) theta rhythm
b) gamma rhythm
c) beta rhythm
d) alpha rhythm

View Answer

Answer: d [Reason:] The alpha rhythm is the principal component of the EEG and is an indicator of the state of alertness of the brain. It serves as an indicator of the depth of anesthesia in the operating room. The frequency of the EEG seems to be affected by the mental activity of a person.

Set 2

1. Which of the following is preferred electrode for measuring EMG?
a) surface electrodes
b) needle electrodes
c) pregelled electrodes
d) scalp electrodes

View Answer

Answer: b [Reason:] Electrodes for EMG work are usually of the needle type. Needle electrodes are used in clinical EMG, neurography and other electrophysiological measurements of the muscle tissues underneath the skin. Surface electrodes are preferred to measure ECG. Scalp electrodes for EEG.

2. Generally what is the material of needle electrodes?
a) stainless steel
b) copper
c) lead
d) iron

View Answer

Answer: a [Reason:] The material of the needle electrode is generally stainless steel. In spite of the face that stainless steel is unfavorable electrode material from the point of view of noise, it is preferred in EMG work. It is due to its mechanical solidity and low price.

3. Monopolar needle electrodes are having coatings of which material over the stainless steel wires which are bare only at the tips?
a) carbon
b) calcium
c) sodium
d) teflon

View Answer

Answer: d [Reason:] The monopolar needle electrode consists of a teflon coated stainless steel wire. The wire is bare only at the tip. It is found that after the needle has been used a number of times, the teflon coating will recede, increasing the tip area. The needle should be discarded when this happens.

4. Which electrode can be used to pick up signals from individual fibers of muscle tissues?
a) biopolar needle electrode
b) concentric core needle electrode
c) multi-element needle electrode
d) monopolar needle electrode

View Answer

Answer: c [Reason:] Multi-element needle electrodes are used to pick up the signals from individual fibers of muscle tissue. Special needles are available using 25-micron diameter electrode surfaces. They have up to 14 pickup surfaces down the side of one needle.

5. _______________ instrument is used to hold patients head and guide the placement of electrodes.
a) Monotaxic
b) Stereotonic
c) Stereotaxic
d) Monotonic

View Answer

Answer: c [Reason:] For measurement of potential from specific part of the brain, longer needles are inserted inside the head. The needles are precisely located by means of a map or atlas of the brain. A special instrument called stereotaxic instrument is used to hold the subject’s head and guide the placement of the electrodes.

6. Number of cloud deployment models that are recognized are ____
a) 2
b) 5
c) 3
d) 4

View Answer

Answer: c [Reason:] There are 3 recognized cloud deployment models. They are – Private cloud, Public cloud and Hybrid cloud.

7. The ground electrode is usually positioned over which body structures?
a) bony
b) hairy
c) fleshy
d) sweaty

View Answer

Answer: a [Reason:] The ground electrode is usually positioned over bony structures rather than over large muscle masses, in the vicinity of the recording and stimulating electrodes, and where possible, equidistant from them. Hairy areas don’t transmit proper signals. It increases impedance of the skin.

8. When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, ________ electrodes are used.
a) plate shape electrodes
b) surface electrodes
c) thin thread electrodes
d) fine wire electrodes

View Answer

Answer: d [Reason:] When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, thin and flexible fine wire electrodes are used. These electrodes are inserted into the muscle site of interest. The needle or steel cannula is removed, and the electrode wires are connected to the steel spring adapters to minimize movement artefacts.

9. The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers. Record of this action potential is called______________
a) ECG
b) EMG
c) EEG
d) EKG

View Answer

Answer: b [Reason:] The contraction of the skeletal muscles results in the generation of action potential in the individual muscle fibers, a record of such action potential is known as electromyogram (EMG). The activity is similar to that observed in the cardiac muscles (ECG or EKG), but in the skeletal muscles, repolarization takes place much more rapidly. The action potential lasts for only few milliseconds.

10. In voluntary contraction of the skeletal muscles, the muscle potential ranges from ________
a) 50 uV – 5 mV
b) 50 mV – 5 V
c) 0.05 uV – 2 mV
d) 50 mV – 500 mV

View Answer

Answer: a [Reason:] In voluntary contraction of the skeletal muscles, the muscle potential ranges from 50 uV – 5 mV and duration from 2 to 15 ms. The values vary with the anatomic position of the muscle and the size and location of the electrode. In a relaxed muscle there are no action potentials.

Set 3

1. The filter used to reject the 50Hz noise picked up from power lines or machinery is called?
a) band reject filter
b) band stop filter
c) notch filter
d) all reject filter

View Answer

Answer: c [Reason:] Such filters are called notch filters. Almost all measuring and recording applications are subjected to some degree of 50Hz noise picked up from the power lines or machinery. Therefore, most signal conditioners include low pass filter designed specifically to provide maximum rejection of 50 Hz noise.

2. Devices that pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique are called?
a) filters
b) rectifiers
c) bridges
d) isolaters

View Answer

Answer: d [Reason:] Such devices are called isolaters. Improper grounding of the system is one of the most common causes of measurement problem and noise. Signal conditioners with isolation can prevent these problems. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.

3. Which of the following technique is not employed in isolation devices?
a) resistance
b) optical
c) inductance
d) capacitance

View Answer

Answer: a [Reason:] Resistance technique is not employed in making isolation devices. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.

4. To achieve the low frequency response for medical applications, the amplifier configuration must contain?
a) higher resistance
b) higher capacitance
c) lower resistance
d) lower capacitance

View Answer

Answer: b [Reason:] To achieve the low frequency response required for medical applications, the amplifier must have large values of coupling capacitance. In all RC-coupled amplifiers, low frequency response is limited by reluctance of the coupling capacitors. The response should be down to less than one hertz which is a very frequent requirement.

5. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
a) True
b) False

View Answer

Answer: a [Reason:] It is true. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.

6. Strain gauges are resistance devices in a Wheat stone bridge configuration _________
a) which does not requires bridge completion circuitry and an excitation source
b) which requires bridge completion circuitry and an excitation source
c) which neither requires bridge completion circuitry nor an excitation source
d) which requires bridge completion circuitry but does not an excitation source

View Answer

Answer: b [Reason:] Strain gauges are resistance devices in a Wheat stone bridge configuration which requires bridge completion circuitry and an excitation source. These devices require external voltage or current excitation. Signal conditioning part of the measurement system usually provides the excitation signals.

7. Which of the following voltage regulator IC gives a variable positive voltage?
a) LM317
b) LM337
c) 7805
d) 7812

View Answer

Answer: a [Reason:] LM317 is a variable positive voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from 1.25V- 30V ideally. LM337 is a variable negative voltage regulator IC. 7805 and 7812 are fixed voltage regulator IC that give output voltage as 5V and 12V respectively .

8. ________ IC is a variable negative voltage regulator.
a) 7912
b) 7905
c) LM337
d) LM317

View Answer

Answer: c [Reason:] LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from (-1.25V) – (-30V) ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.

9. Digital filters are sensitive to temperature as compared with analog filters.
a) True
b) False

View Answer

Answer: b [Reason:] False. Digital filters are insensitive to temperature as compared with analog filters. The are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Theri response is completely reproducible and predictable, and software simulations can exactly reflect product performance.

10. Signal conditioning is not of much importance in the measuring and recording system.
a) True
b) False

View Answer

Answer: b [Reason:] Signal conditioning is of great importance in measuring and recording system. They determine the range, accuracy and resolution of the system. Signal conditioning includes either hardware based or software based linearization routines for this purpose.

Set 4

1. Potentiometer works on which of the following principle?
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable electromagnet

View Answer

Answer: a [Reason:] Potentiometer works on the principle of variable resistance. The resistance between two terminals of this device is related to the linear or angular displacement of a sliding tape along a resistance element. When the fixed terminals of the potentiometer are connected to the power supply. Either ac or dc, output voltage at the wiper varies with the displacement of the object.

2. On increasing the distance between the plates of a variable capacitor, the displacement- capacitance characteristics changes _______
a) proportionally
b) linearly
c) exceptionally
d) hyperbolically

View Answer

Answer: d [Reason:] By moving one plate of the capacitor with respect to the other, the capacitance will vary inversely with respect to the plate separation. This will give a hyperbolic displacement capacitance characteristic. This is how variable capacitance is employed as displacement transducers.

3. Lateral displacement of capacitance plates with respect to each other gives linear displacement -capacitance characteristics?
a) True
b) False

View Answer

Answer: a [Reason:] It is true that lateral displacement of capacitance plates with respect to each other gives linear displacement -capacitance characteristics. C = 0.0885*k*(A/d). k= dielectric constant of the medium separating the two plates. C= capacitance in micro farads A= area of each identical plate in cm2 d= distance between the plates in cm2.

4. LVDT stands for _________
a) Linear Virtual Double Transformer
b) Linear Virtual Differential Transducer
c) Linear Variable Differential Transducer
d) Linear Variable Differential Transformer

View Answer

Answer: d [Reason:] LVDT stands for Linear Variable Differential Transformer. These transducers are conventionally used for measurement of physiological pressure. They generally work in conjunction with carrier amplifiers.

5. LVDT works on the principle of ________
a) variable resistance
b) variable inductance
c) variable capacitance
d) variable pressure

View Answer

Answer: b [Reason:] LVDT works on the principle of variable inductance. It has three coils namely the primary coil which is the center coil. The other two are called the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.

6. In LVDT the secondary coils are energized with sine wave oscillator?
a) True
b) False

View Answer

Answer: b [Reason:] The center coil is the energizing or primary coil connected to a sine wave oscillator. The secondary coils so connected that their outputs are equal in magnitude but opposite in phase. LVDT works on the principle of variable inductance.

7. How many coils are required to make LVDT?
a) 4
b) 6
c) 3
d) 2

View Answer

Answer: c [Reason:] Total 3 coils are required in LVDT. One centered coil which is the energizing or primary coil connected to the sine wave oscillator. The other two coils are the secondary coils so connected that their outputs are equal in magnitude but opposite in phase.

8. LVTD is a _______ transducer.
a) displacement
b) photoelectric
c) thermal
d) chemical

View Answer

Answer: a [Reason:] LVDT is a displacement transducer. It works on the principle of variable inductance. The shift in the ferromagnetic core from the centre position induces voltage in the second coild which can be calibrated to determine the linear displacement.

9. Which of the following is a displacement transducer?
a) thermistor
b) LVDT
c) strain gauge
d) thermocouple

View Answer

Answer: b [Reason:] LVDT is a displacement transducer. Thermocouple and thermistor are temperature transducers. Strain gauge is a pressure transducer.

10. Linear encoders gives ___________ output.
a) angular
b) analog
c) digital
d) unstable

View Answer

Answer: b [Reason:] Linear encoders give output in digital form. These transducers are basically encoded disks or rulers with digital pattern photographically etched on glass plate. These patterns are decoded using a light source and an array of photodetectors.

Set 5

1. Which type of electrodes are employed to study the electrical activities of individual cells?
a) milli-electrodes
b) micro-electrodes
c) surface-electrodes
d) pre-jelled electrodes

View Answer

Answer: b [Reason:] To study the electrical activities of individual cells, micro electrodes are employed. This type of electrode is small enough with respect to the size of the cells. Typical micro electrodes have tip dimensions ranging from 0.5-5 microns.

2. Glass micro-capillaries are a type of micro electrode.
a) True
b) False

View Answer

Answer: a [Reason:] Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.

3. Glass microcapillaries are preferred over metallic electrodes because the former _______
a) polarizes with input current.
b) does not have sustainable current carrying capacity.
c) has less contact surface area.
d) Has sustainable current carrying capacity.

View Answer

Answer: d [Reason:] Metallic electrodes polarize with smaller amplifier input currents. Hence, they tend to develop unstable electrode offset potential and are therefore not preferred for steady state potential measurement. On the other hand , in case of glass micro electrodes have a sustainable current carrying capacity because of the large surface area between the metal and the electrolyte.

4. Do metallic micro electrodes exist?
a) True
b) False

View Answer

Answer: a [Reason:] Two types of micro electrodes are generally used: metallic and glass microcapillaries. Metallic electrodes are formed from a fine needle of suitable metal drawn for a fine tip. Glass electrodes are drawn from Pyrex glass of special grade.

5. Metallic micro electrodes have impedance ________ compared to conventional electrodes?
a) equal
b) smaller
c) high
d) very high

View Answer

Answer: d [Reason:] The very high impedance of the metal micro-electrodes is due to the characteristics of the small area metal-electrolyte interface. Because of very high impedance of micro electrodes, amplifiers with extremely high input impedance are required to avoid loading the circuit and to minimize the effects of small change in interface impedance.

6. Which of the following electrode is manufactured by circumferential application of heat to a small area of glass tubing and pulling the glass when it gets soft?
a) macro metallic electrodes
b) micro metallic electrodes
c) micro pipette
d) surface electrodes

View Answer

Answer: c [Reason:] The most commonly used method for making small tip micropipette consists of the circumferential application of heat to a small area of glass tubing which is placed under some initial tension. When the glass softens, the tension is increased very rapidly and the heat is turned off. Proper timing, controlled adjustment of the amount of heat as well as the initial and final tensions and cooling results in the production of microcapillaries with control dimensions.

7. Which of the following metal is preferred for manufacturing micro electrodes?
a) Stainless steel
b) Tungsten
c) Iron
d) Copper

View Answer

Answer: b [Reason:] Tungsten is preferred for constructing micro-electrodes due to its mechanical strength and its apparent inertness. Although tungsten itself is reactive, a surface layer of tungsten oxide will, in most situations, protect the metal against corrosion.

8. ________________ are devices which convert one form of energy into another.
a) transducers
b) electrodes
c) impulses
d) opamp

View Answer

Answer: a [Reason:] Transducers are devices which convert one form of energy into another. A number of factors decide the choice of a particular transducer to be used for the study of a specific phenomenon. Many physical, chemical and optical properties and principles can be applied to construct transducers for applications in the medical field.

9. When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, ________ electrodes are used.
a) plate shape electrodes
b) surface electrodes
c) thin thread electrodes
d) fine wire electrodes

View Answer

Answer: d [Reason:] When intramuscular EMG is required to look into the electrical activities of deeper or overlaid muscles, thin and flexible fine wire electrodes are used. These electrodes are inserted into the muscle site of interest. The needle or steel cannula is removed, and the electrode wires are connected to the steel spring adapters to minimize movement artefacts.

10. In floating electrodes metal electrode does not make direct contact with the skin.
a) True
b) False

View Answer

Answer: a [Reason:] In floating electrode the metal electrode does not make direct contact with the skin. The electrode consists of a light weighted metalled screen or plate held away from the subject by a flat washer which is connected to the skin. Floating electrodes can be recharged, i.e. the jelly in the electrodes can be replenished if desired.

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