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Correct option is (a) 10 mm/mV

For explanation I would say: Time measurements and heart rate measurements are made HORIZONTALLY on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm INTERVALS with a thicker line at 5 mm intervals. Amplitude measurements are made vertically in millivolts. The sensitivity of an ELECTROCARDIOGRAPH is typically set at 10 mm/mV.

The CORRECT option is (c) Electrodes

For explanation: EEG preamplifiers are GENERALLY designed to have a very HIGH value of input impedance to take care of high ELECTRODE impedance. Good electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be balanced or the DIFFERENCE between them should be less than 2 kilohms.

The correct answer is (B) Monochromators

The best explanation: Monochromators are optical SYSTEMS, which provide better isolation of spectral energy than the optical filters, and are therefore PREFERRED where it is required to isolate narrow bands of radiant energy. Monochromators USUALLY incorporate a small GLASS of quartz prism or a diffraction grating system as the dispersing media.

Right answer is (c) optical fibre

Best EXPLANATION: For intravascular oximetry, modern instruments make use of optical fibres to guide the LIGHT SIGNAL inside the VESSEL and the reflected light from the red blood cells back to the light detector.

Correct option is (a) integrated platelet volume to the platelet count

The best explanation: Mean Platelet Volume (MPV) is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres. Platelet Distribution Width is related to the size range COVERED by those platelets lying between the SIXTEENTH and EIGHTY fourth percentile. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red CELLS.

Correct OPTION is (b) ELECTROCHEMICAL

Best explanation: The biosensor in this instrument relies upon enzymes that RECOGNISE and catalyze REACTIONS of glucose with the generation of redox – active species that are detected electrochemically. Home blood glucose detection SENSOR works on the principle of electrochemical.

The correct answer is (b) For Stabilizing effect

For explanation: The preamplifier is usually a three or FOUR STAGE DIFFERENTIAL amplifier having a sufficiently LARGE negative CURRENT feedback, from the end stage to the first stage, which gives a stabilizing effect.

Right answer is (b) ECG

The best I can explain: CMRR of the order of 100–120 DB with 5 KW unbalance in the leads is a desirable FEATURE of ECG machines. In addition to this, under specially adverse circumstances, it becomes necessary to include a notch filter tuned to 50 Hz to reject HUM due to power mains.

Right ANSWER is (a) True

Easiest explanation: It is True. On applying PRESSURE to piezo-electric crystal, electricity is generated. The piezo electric effect is a property of a natural crystalline substance to develop electric potential ALONG a crystallographic axis in response to the movement of charge as a result of MECHANICAL deformation. Thus, piezo-electricity is pressure electricity.

Correct choice is (b) EMG

Explanation: Electromyograph is an instrument used for recording the electrical activity of the muscles to determine whether the MUSCLE is CONTRACTING or not; or for displaying on the CRO and loudspeaker the action potentials spontaneously present in a muscle or those induced by VOLUNTARY contractions as a means of detecting the nature and location of motor unit lesions; or for recording the electrical activity EVOKED in a muscle by the stimulation of its nerve.

Right option is (a) TAPE Recorder

To explain: The waveform can also be photographed from the CRT screen by using a synchronized camera. The tape recorder is included in the system to facilitate playback and study of the EMG sound waveforms at a LATER CONVENIENT TIME.

Correct option is (b) Very low CMRR

To elaborate: Instrumentational amplifiers have very HIGH CMRR. The INSTRUMENTATION amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input IMPEDANCE, low bias and offset currents, high slew rate.

Right answer is (d) LOWER part of the heart wall between the two atrial

The best I can explain: The AV node delays the spread of excitation for about 0.12s, DUE to the PRESENCE of a fibrous barrier of non-excitable cells that effectively prevent its PROPAGATION from continuing beyond the limits of stria.The AV node is located in the lower part of the wall between the two atria.

Right answer is (c) high contact impedance

Easy explanation: It has a high contact impedance as only the rim of the ELECTRODE is in contact with the skin. WELSH cup electrodes or SUCTION electrodes is a metallic cup SHAPED electrode which is used for recording ECG from various positions from the chest.It is commonly used to record the unipolar chest leads.

Correct answer is (a) TRUE

Explanation: It is True. The PIEZO electric effect is a PROPERTY of a NATURAL crystalline substance to develop electric potential along a crystallographic axis in response to the movement of charge as a result of mechanical deformation. On applying electricity to the piezo-electric material mechanical deformation occurs in the material.

Correct OPTION is (c) Control and timing

Best explanation: It also handles individuals functions such as keyboard and direct writer interface, tape deck control, timing data processing, and ARRHYTHMIA count TOTALIZING via a high SPEED interrupt SYSTEM. The control and timing CPU has an overall system control responsibility.

Right CHOICE is (d) Mercury arc

The explanation: Modern INSTRUMENTS use a tungsten-halogen light source, which has a higher intensity OUTPUT than the NORMAL tungsten lamp in the change over a region of 320–380 nm used in colorimetry and spectrophotometry. It also has a larger life and does not suffer from blackening of the bulb glass ENVELOPE.

The correct answer is (a) dc BRIDGE amplifier

For explanation: Essentially, the amplifier comprises a stable dc EXCITATION source, a bridge balance and calibration unit, a high gain differential dc amplifier and a dc OUTPUT amplifier.DC bridge amplifiers are employed with resistive TRANSDUCERS which require an external source of excitation. They can be used as conventional dc high gain amplifiers and offer operating simplicity and high FREQUENCY response.

The correct answer is (a) above certain value

The BEST I can explain: High pass FILTER amplifies SIGNAL above a certain FREQUENCY. Band pass filter amplifies frequencies with in a certain band. Band stop filter amplifies all the frequencies except those in a certain band. Low pass filter amplifies signals below a certain frequency.

The correct CHOICE is (c) Time Measurements

To EXPLAIN I would say: Time measurements and heart RATE measurements are made horizontally on the electrocardiogram. Electrocardiograms are almost invariably recorded on graph paper with horizontal and vertical lines at 1 mm intervals with a thicker line at 5 mm intervals.Amplitude measurements are made vertically in millivolts. The sensitivity of an electrocardiograph is TYPICALLY SET at 10 mm/mV.

The CORRECT option is (a) True

The best explanation: EEG electrodes are smaller in size than ECG electrodes. Several types of electrodes may be used to RECORD EEG. These include: Peel and Stick electrodes, Silver plated CUP electrodes and Needle electrodes.

The CORRECT choice is (b) Plateletcrit

To elaborate: Plateletcrit is the PERCENTAGE of the total specimen volume occupied by the PLATELETS. Red Cell Distribution Width is a numerical expression of the width of the size distribution of red CELLS. MEAN Platelet Volume is the ratio of the integrated platelet volume to the platelet count and is expressed in femolitres.

Right option is (a) ECG(Electrocardiograph)

To ELABORATE: Electrical signals from the heart characteristically precede the normal mechanical FUNCTION and monitoring of these signals has great clinical significance.The electrocardiograph (ECG) is an INSTRUMENT, which records the electrical ACTIVITY of the heart.

The correct answer is (d) biocatalytic membrane

The BEST I can explain: The biocatalytic membrane accomplishes the conversion of reactant to product. The product of the reaction diffuses to the TRANSDUCER. The BIOLOGICAL response of the biosensor is determined by biocatalytic membrane.This then CAUSES the ELECTRICAL response.

Right OPTION is (c) six

The best I can EXPLAIN: The third LEAD is in series with the power supply and is therefore independent of bridge balance.Compensation for temperature variation in the leads can be provided by using three lead methods. In this method, TWO of the leads are in the adjacent legs of the bridge which cancels their RESISTANCE changes and does not disturb the bridge balance.

The correct option is (a) quartz

To EXPLAIN I would SAY: Quartz is the most STABLE natural crystal with high mechanical and thermal stability and has volume RESISTIVITY higher than 10^4 ohm-cm and small internal electric loss. Barium titanate ceramic is a ferroelectric crystal and has small voltage output. ALUMINIUM is not a piezo-electric material.

The correct option is (a) 60

Explanation: EEG machines have a notch FILTER sharply tuned at 60 Hz so as to eliminate mains frequency interference. The use of notch filters should preferably be restricted to exceptional circumstances when all other methods of eliminating interference have been found to be ineffective. These however have the undesirable PROPERTY of ‘ringing’ i.e. they produce a DAMPED OSCILLATORY response to a square wave calibration WAVEFORM or a muscle potential.

Correct choice is (b) RESISTIVE coupled isolation AMPLIFIERS

The best I can explain: Opto-coupled amplifier uses a MINIMUM number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive. There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common USE, THOUGH the transformer isolation amplifier is more popular.

Right CHOICE is (a) time measurements and HEART rate measurements

To elaborate: Time measurements and heart rate measurements are made HORIZONTALLY on the electrocardiogram. Electrocardiograms are almost invariably recorded on GRAPH paper with horizontal and vertical lines at 1 mm intervals with a THICKER line at 5 mm intervals.

Right answer is (b) high impedance SIGNALS to low impedance signals

The best I can explain: A buffer amplifies is essentially an impedance CONVERTER, that converts high impedance signals to low impedance signals. NOISE is typically generated from motion artefacts and power line interference. A common solution USED to SUPPRESS noise in dry electrode signals is a buffer amplifier.

Right answer is (b) sino-atrial node

The best explanation: Located in the TOP right atrium near the entry of the vena cava, are a group of cells known as the sion-atrial node (SA node) that initiates the heart activity. Because of this is ALSO considered as the primary pacemaker of the heart. The SA node is 25 to 30 mm in LENGTH and 2 to 5 mm in thickness.

Correct choice is (d) PHOSPHOR BRONZE

To EXPLAIN: The motion of the diaphragm is measured in terms of electric signals. Tourmaline, barium titanate and zirconate titanate are piezo electric materials.Phosphor bronze is used to MAKE diaphragm to measure PRESSURE.

The correct option is (b) 0.1 to 70 Hz

For explanation I would say: The TYPICAL frequency RANGE of standard EEG MACHINES is from 0.1 Hz to 70 Hz, THOUGH newer machines allow the detection and filtering of frequencies up to several HUNDRED Hertz. This may be of importance in some intracranial recordings.

Right option is (b) EEG

To explain: EEG electrodes give high SKIN contact impedance as COMPARED to ECG electrodes. GOOD electrode impedance should be generally below 5 kilohms. Impedance between a pair of electrodes must also be BALANCED or the difference between them should be less than 2 kilohms.

Right option is (a) Isolation AMPLIFIERS

For EXPLANATION I WOULD SAY: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation BARRIER.

Correct answer is (b) [(20^th – 80^th) PERCENTILE Volume / (20^th + 80^th) Percentile Volume] X 100 X K

The best I can explain: The total erythrocyte count is SCANNED by a continuously variable thresholding circuit. The RDW index is expressed by the following equation [(20^th – 80^th) Percentile Volume / (20^th + 80^th) Percentile Volume ] X 100 X K. It is a numerical expression of the width of the size distribution of red cells. It is DERIVED by analog computation. The upper threshold is MOVED progressively lower from a level equivalent to 360 femolitres until 20 per cent of all erythrocytes present have a size above a certain value.

Correct choice is (c) multiple grounding

For explanation: Electromagnetic COUPLING is reduced by shielding, wire TWISTING and proper grounding which provide a BALANCED signal pair with satisfactory noise rejection characteristics. Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may COMPLETELY obscure the USEFUL signal.

The correct answer is (a) Cardiographic beat

To explain: These are bradycardia, TACHYCARDIA, DROPPED beat and premature beat. The analyzer part in automatic scanning of ambulatory RECORDS looks for four arrhythmic conditions.A THRESHOLD control is associated with each of these and when the appropriate threshold is exceeded, an alarm CONDITION is generated.

Right choice is (c) gauge FACTOR

The explanation is: Gauge factor gives information on the expected resistance change or output SIGNAL at maximum permissible elongation. The gauge factor determines to a large extent the sensitivity of the wire when it is made into a practical strain gauge. The figure of merit which describes the overall behaviour of the wire under stress is DETERMINED from the gauge factor of the wire.

Right option is (a) optical FIBER

Explanation: They contain a RARE EARTH phosphor which is illuminated by a white light along a short LENGTH of large core optical fibre. Fluoroptic temperature sensors work on the principle of optical fiber sensors.The light excites the phosphor which emits a number of lines. By using filters, two of these lines at 540 and 630 nm are selected, and the ratio of their intensities is a SINGLE valued function of the temperature of the phosphor.

The CORRECT option is (a) True

To explain I would say: There is a SMALL needle at the tip of the machine that pierces the skin to take a blood SAMPLE. Home blood glucose measurement DEVICES measure the glucose level through invasive method. This blood is then undergoes electrochemical reactions and the glucose level is determined.

Correct choice is (b) smart pad

The best I can explain: The SYSTEM automatically selects three electrodes from an array of Cu/Ni fabric based electrodes patterned on a thin pad on which the patient LIES. The smart pad is a system that displays a patients electrocardiogram signals without adhesive pads, wires or ACTIVE intervention from a clinician. The selected electrodes are USED to provide a differential 3 lead measurement of the patient’s ECG, which is then transmitted wirelessly and DISPLAYED on a laptop computer.