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The correct answer is (d) 15 to 60 %

Easiest explanation: Interference filters allow a much narrower BAND of WAVELENGTHS to pass and are similar to MONOCHROMATORS in selectivity. They are simpler and less expensive. However, as the selectivity increases, the TRANSMITTANCE decreases. The transmittance of these filters varies between 15 to 60 PERCENT with a spectral bandwidth of 10 to 15 nm.

Correct choice is (b) Tungsten-halogen lamp

The best explanation: Modern instruments USE a tungsten-halogen light source, which has a HIGHER intensity output than the normal tungsten lamp in the change over the region of 320–380 NM used in colorimetry and spectrophotometry. It ALSO has a larger life and does not suffer from the blackening of the bulb glass envelope.

The correct option is (d) Tungsten lamp

The best explanation: The most common and convenient source of light is the tungsten lamp. This lamp consists of a tungsten FILAMENT enclosed in a glass envelope. It is cheap, intense and reliable. A major portion of the ENERGY emitted by a tungsten lamp is in the visible REGION and only about 15 to 20% is in the INFRARED region.

Correct option is (d) 2 to 2.5 MHz

The BEST explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is usually employed, whereas in the study of BLOOD FLOW in arteries and SUPERFICIAL blood vessels frequencies around 5–10 MHz are preferred. The LEVEL of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm^2.

The correct CHOICE is (c) Foetus blood flow detector

Best explanation: An important clinical INSTRUMENT for obstetric applications which makes USE of the Doppler shift PRINCIPLE is the foetus blood flow detector. The technique is extended to DERIVE an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display system.

The correct option is (c) 230 ms

The explanation: After PEAK detection, the processed pulses operate a one-shot CIRCUIT which gives a fixed PULSE width of 230 ms. The output of one-shot triggers a variable pulse width multi-vibrator which adds and gives either 43 or 116 ms time depending on the heart RATE. The pulse width at the output will be either 230 + 43 = 273 ms or 230 + 116 = 346 ms.

The correct option is (C) 0.3 liters

To explain I would say: Studies of DILUTE or weakly-absorbing LIQUID samples, or of samples where trace components must be detected, require a cell with a long path-length. For such applications, a 50 cm path-length with about a 300 ML volume cell is EMPLOYED.

Right option is (a) True

To explain I WOULD say: The absorption TYPE optical filter usually consists of colour MEDIA: colour glasses, coloured films (gelatin, etc.), and SOLUTIONS of the coloured substances. This type of filter has a wide spectral BANDWIDTH, which may be 40 to 50 m in width at one-half the maximum transmittance.

Correct choice is (d) 210 NM

Easy explanation: Normally, the absorbance of any material should be less than 0.2 at the wavelength of use. Below 300 nm, QUARTZ or FUSED silica is utilized. The limit for quartz is 210 nm.

Correct ANSWER is (b) Monochromators

For 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.

The correct ANSWER is (c) 400

To elaborate: No output PULSE will occur if the period between TWO pulses is LESS than 400 MS. The 20 ms pulses are, therefore, not generated and the integrator discharges slowly from the negative output voltage to a positive output voltage. If the output of the integrator (6) is less negative than-V, the output of the comparator (7) will become negative.

Correct choice is (a) Cardiographic BEAT

For explanation: The analyzer part in automatic scanning of ambulatory records look for four arrhythmic conditions. These are bradycardia, TACHYCARDIA, dropped beat and premature beat. A threshold control is associated with each of these and when the APPROPRIATE threshold is EXCEEDED, an alarm condition is generated.

The correct option is (a) 60, 40

The best explanation: The LIQUID PART of the blood—the blood plasma, and the formed elements—the blood cells are analyzed during a CHEMICAL examination. The blood plasma accounts for about 60% of the blood volume and the blood cells occupy the other 40%. The plasma is obtained by centrifuging a blood sample.

The correct answer is (a) ml = 2d SIN Q, where L= lambda

To explain I would say: The expression relating the wavelength of the radiation and the angle (q) at which it is reflected is given by

ml = 2d sin q, where l= lambda.

where d is the distance separating the grooves and is known as the grating constant and m is the order of interference.

When m = 1, the SPECTRUM is known as first order and with m = 2, the spectrum is known as second order.

The correct answer is (c) CONTROL and TIMING

Explanation: The control and timing CPU has an overall system control responsibility. 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 CORRECT ANSWER is (c) Deuterium discharge lamp

Best explanation: For work in the ULTRAVIOLET region, a hydrogen or deuterium discharge lamp is used. In these LAMPS, the envelope material of the lamp PUTS a limit on the smallest wavelength which can be transmitted.

The correct choice is (b) Benz

To elaborate: An excellent review of ambulatory CARDIAC event recorders is PROVIDED by Benz in 1999. The major advantage of these devices compared with a traditional Holter monitor is that they are small, ALLOW ECG monitoring for longer time periods, and can provide NEARLY REAL time data analysis when the patient transmits a recording in proximity to the symptomatic event.

The correct CHOICE is (b) Sensitive Microphone

To explain I would say: Foetal heart sounds can be picked up from the maternal abdomen by a sensitive microphone. The heart sounds in the FORM of mechanical vibrations have to pass through tissue structure and the signals picked up are RATHER WEAK because of distance effects and the small size of foetal heart valves.

Right option is (B) Transmittance

Explanation: Let us suppose, Po is the INCIDENT radiant ENERGY and P is the energy which is TRANSMITTED. The ratio of the radiant power transmitted by a sample to the radiant power incident on the sample is known as the transmittance.

Transmittance = P/Po

The correct choice is (c) MAGNESIUM Flouride

The EXPLANATION is: Reflections from glass SURFACES are reduced by coating these with magnesium fluoride, which is one-quarter wavelength in optical thickness. With this, SCATTERING effects are also GREATLY reduced.

Right option is (c) Diffraction gratings

The best I can explain: Most modern instruments now use a diffraction grating as a dispersing ELEMENT in the monochromator, as prisms in general have a poorer stray light performance and require complex precision cams to GIVE a linear wavelength scale. Replica gratings can even be produced more CHEAPLY than prisms and require only a simple sine BAR MECHANISM for the wavelength scale.

Correct choice is (b) False

The best explanation: False, to detect the HEART frequency, the 400 ms one-shot is used. If the period duration is greater than 400 ms, the one-shot will deliver a pulse. The NEGATIVE SLOPE of this pulse is used to trigger the 20 ms one-shot. These 20 ms PULSES are integrated by the integrator and the OUTPUT of this integrator is compared with a fixed voltage -V.

The CORRECT option is (b) False

The explanation is: False, PHONOCARDIOGRAPHY provides a basically cleaner signal than does ultrasound, thus allowing a greater chance of detecting a smooth BASELINE FHR. Unfortunately, phonocardiography is more susceptible to artefacts introduced from ambient noise, PATIENT movement or other intra-abdominal sounds.

Correct option is (b) Mirrors

The explanation is: To minimize light losses, lenses are sometimes replaced by front-surfaced mirrors to focus or COLLIMATE light BEAM in absorption instruments. Mirrors are aluminized on their front surfaces. With the USE of mirrors, chromatic ABERRATIONS and other imperfections of the lenses are MINIMIZED.

Correct option is (c) 380 to 780 nm

Explanation: The region in the ELECTROMAGNETIC spectrum which is normally used in spectroscopic work is very limited. Visible light represents only a very SMALL portion of the electromagnetic spectrum and GENERALLY covers a RANGE from 380 to 780 nm. The ultraviolet region EXTENDS from 185 mm to the visible.

The correct ANSWER is (C) 10-15 mW/cm^2

The best explanation: For obstetric studies, ultrasonic frequency of about 2 to 2.5 MHz is USUALLY employed, whereas in the study of blood flow in arteries and superficial blood vessels FREQUENCIES around 5–10 MHz are preferred. The LEVEL of ultrasonic energy transmitted into the body is generally kept between 10–15 mW/cm^2.

The correct OPTION is (d) ABSORPTION spectrophotoscopy

The explanation is: Electronic transitions correspond to the ultraviolet and visible regions, vibrational transitions to the NEAR infrared and infrared regions and rotational transitions to the infrared and far-infrared regions. The method based on the absorption of radiation of a substance is known as Absorption Spectroscopy.

Right option is (a) True

To explain: In Real-Time Continuous CARDIAC MONITORING Systems, the MONITOR is equipped with software that analyzes the rhythm DATA continuously and automatically. The monitor automatically transmits recorded data transtelephonically (by wireless network or land phone line) to a CENTRAL monitoring station for subsequent analysis when an arrhythmia is detected by an arrhythmia algorithm.

The correct choice is (c) Time RECORDERS

For explanation I would say: Currently, the following FOUR types of systems are available for ambulatory ECG monitoring: I) Holter MONITORS II) Event Recorders III) Real-Time Continuous Cardiac Monitoring SYSTEM IV) IMPLANTABLE Loop Recorders.

Right option is (C) Spectrophotometry

Best EXPLANATION: Spectrophotometry is the most important of all the instrumental METHODS of analysis in CLINICAL chemistry. This method is BASED on the absorption of electromagnetic radiation in the visible, ultraviolet and infrared ranges.

Correct choice is (c) Ultrasound

To explain: An IMPORTANT clinical instrument for obstetric applications which makes use of the DOPPLER shift principle is the foetus BLOOD flow detector. The ultrasound technique is extended to derive an integrated rate of the foetus heart from blood flow signals and to display it on a suitable display SYSTEM.

The correct choice is (C) GAMMA rays

The best I can EXPLAIN: Electromagnetic spectrum ranges from very short WAVELENGTHS (including gamma and X-rays) to very LONG wavelengths (including microwaves and broadcast radio waves). The range of wavelength of gamma rays and X-rays is 10^-4 to 10 nm. The range of wavelengths of microwaves and radio-waves is 10^6 to 10^9 nm.

The correct choice is (a) 800 NM

Explanation: A typical REFLECTION grating may have 1200 GROOVES/mm, which MEANS the grooves are spaced at about 800 nm INTERVALS. The grating may have a width of 20 mm or more, giving a total of at least 24,000 grooves.

Right option is (C) LITTROW mounting

For explanation I would SAY: Quartz SHOWS the property of double refraction. Therefore, two pieces of quartz, one right-handed and one left handed are taken and cemented back-to-back in the construction of 60° prism (Cornu mounting), or the energy must be reflected and returned through a SINGLE 30° prism, so that it passes through the prism in both directions (Littrow mounting).

The correct choice is (d) Planar-Fashionable Circuit Board

To elaborate: The full form of F-PCB is Planar-Fashionable Circuit Board. Sometimes in Holter monitoring, the PATIENT needs typically 6 to 10 wires worn around the body THROUGHOUT the DAY. To overcome these problems, a WEARABLE electrocardiogram acquisition system implemented with planar-fashionable circuit board (F-PCB)-based shirt is explained by Yoo.

Correct option is (b) 400 ms ONE shot

Best EXPLANATION: To DETECT the heart frequency, the 400 ms one-shot is used. If the period DURATION is greater than 400 ms, the one-shot will deliver a pulse. The negative slope of this pulse is used to trigger the 20 ms one-shot. These 20 ms pulses are integrated by the integrator and the OUTPUT of this integrator is compared with a fixed voltage -V.

Right option is (c) 70-110

The explanation: To pick up the heart sounds, it is essential that the transducer be properly placed and its impedance carefully matched. A crystal microphone is used for picking up phono signals. The phono transducer signals are amplified by a low noise preamplifier and fed to a BANDPASS FILTER which REJECTS all frequencies outside the 70 to 110 Hz RANGE.

Right answer is (b) REPLICA grating

To explain: Holographic gratings used in commercial spectrophotometers are either original master gratings produced DIRECTLY by an INTERFEROMETER or are replica gratings. Replica gratings are reproduced from a master holographic grating by moulding its grooves ONTO a resin surface on a GLASS or silica substrate.

Right option is (c) Integrator

To explain: The integrator is USED to DELAY the change in the time CONSTANT and to make sure that a change of on-time takes place only if several (3 to 4) heart beats with the LONGER period DURATION (below 150 bpm) are present.

Correct choice is (B) The light SOURCE and the detector

The explanation is: Gases MAY be contained in cells which are sealed or stoppered to make them air-tight. The sample HOLDER is generally inserted somewhere in the interval between the light source and the detector. For the majority of analyses, a 10 MM path-length rectangular cell is usually satisfactory.

The correct choice is (d) Half-silvered mirrors

Explanation: The two beams must retain the spectral properties of the incident BEAM. Half-silvered mirrors are often used for splitting the beam. However, they absorb some of the LIGHT in the thin metallic coating. Beam splitting can also be ACHIEVED by using a prismatic MIRROR or stack of thin horizontal glass plates, silvered on their edges and ALTERNATIVELY oriented to the incident beam.

Correct answer is (c) ZnS

For explanation: Interference filters USUALLY CONSIST of two semi-transparent layers of SILVER, DEPOSITED on glass by EVAPORATION in a vacuum and separated by a layer of dielectric (ZnS or MgF2). In this arrangement, the semi-transparent layers are held very close.

The correct option is (c) 60 times of recording SPEED

The explanation is: In data RECORDERS, during REPLAY, the tape is run at 120 mm/s (60 times the recording speed) to achieve rapid manual or automatic scanning of ambulatory records. The tape recorders USED for this purpose have some special features as compared to the usually AVAILABLE entertainment tape recorders.

Correct answer is (a) 200 nm, 185 nm

The best explanation: In these lamps, the envelope MATERIAL of the lamp puts a LIMIT on the smallest wavelength which can be transmitted. For example, quartz is SUITABLE only up to 200 nm and fused silica up to 185 nm. The radiation from the discharge lamps is concentrated into narrow wavelength regions of emission lines. Practically, there is no emission BEYOND 400 nm in these lamps.