PMU - Year 1 Physics - Part 3(B)

Question 1 of 59

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According to Stokes shift, if λ is the wavelength of stimulating radiation and λ2 - of the emitted luminescence radiation, then:

Select one of the following:

  • λ1 < λ2;

  • λ1 > λ2

  • λ1 = λ2

Question 2 of 59

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Quantum yield (Wavilov's law) is defined as:

Select one of the following:

  • (Number of emission photons) / (Number of excitation photons)

  • (Number of excitation photons) / (Number of emission photons)

  • (Number of emitted photons) / (Number of excitation photons)

Question 3 of 59

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Phosphorescence is when an electron has returned to singlet (basic) level, passing through an intermediate level that is:

Select one of the following:

  • Singlet

  • Triplet (metastable)

  • Energy level higher than ground level.

Question 4 of 59

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The following statement: "Under the influence of a photon with suitable energy, the electron returns to singlet state from the metastable level" describes:

Select one of the following:

  • Emission of white light

  • Stimulated emission

  • Infrared emission with SoLux (Incandescent lamp used in physical therapy)

Question 5 of 59

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The active medium of a laser must have:

Select one of the following:

  • Short half-life t1/2 of exited states:

  • Acoustic impedance Za matching that of target tissues

  • The possibility for population inversion

Question 6 of 59

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Light is monochromatic when:

Select one of the following:

  • It is a single wavelength λ

  • It propagates in the same direction

  • It propagates in-phase

Question 7 of 59

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The output mirror of laser resonator is:

Select one of the following:

  • Semi-transparent

  • Completely transparent

  • Non-transparent (opaque)

Question 8 of 59

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The laser can be:

Select one of the following:

  • A flux of protons

  • A flux of electrons with the same energy

  • An electromagnetic radiation with specific properties

Question 9 of 59

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The laser is:

Select one of the following:

  • Radionuclide generator for generating metastable radionuclide 99m Tc

  • Generator of light with specific properties

  • Ultrasound generator

Question 10 of 59

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Light generation in a laser is a result of:

Select one of the following:

  • Spontaneous electron transitions

  • Stimulated electron transitions

  • Spontaneous and stimulated transitions of electrons

Question 11 of 59

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Separation of tissue fragments with a laser, without causing necrosis to underlying cells is called:

Select one of the following:

  • Denaturation of proteins

  • Coagulation

  • Photoablation

Question 12 of 59

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Electromagnetic waves are coherent when:

Select one of the following:

  • They oscillate with the same frequency, and with constant phase difference.

  • They have the same wavelength λ

  • They propagate in the same plane.

Question 13 of 59

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What is the definition for population inversion?

Select one of the following:

  • More electrons occupy high energy levels than lower energy levels

  • Fewer electrons occupy high energy levels than lower energy levels

  • There are vacant electron energy levels.

Question 14 of 59

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Laser radiation DOES NOT have the properties of:

Select one of the following:

  • Coherence and polarization

  • Emission in the visible spectrum only

  • Collimation (Directionality)

Question 15 of 59

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What properties summarize laser light the best:

Select one of the following:

  • Monochromatic, Coherent, Collimated

  • Polychromatic, Polarized, Collimated

  • Monochromatic, Coherent, Diffracted

Question 16 of 59

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Lasers produce light with specific properties through:

Select one of the following:

  • Spontaneous emission

  • Stimulated emission

  • Fluorescence

Question 17 of 59

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Laser endoscopes are preferred to light endoscopes. Which of the statements below is NOT a factor for this choice:

Select one of the following:

  • They can eliminate infrared light from the emission spectrum (through a suitable choice of gain medium)

  • They provide optimal illumination of examined organs

  • Examination is more comfortable for the patient

Question 18 of 59

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PDT of endobronchial cancer uses a laser of 630 nm wavelength. In what of the range is this emission:

Select one of the following:

  • UV Range

  • IR Range

  • Visible Range

Question 19 of 59

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In photo-dynamic therapy (PDT), excitation wavelength is specific to the photo-sensitizing drug used. What type of laser light is suitable for HpD photosensitizer with 410 nm emission:

Select one of the following:

  • λ = 390 nm

  • λ = 500 nm

  • λ = 630 nm

Question 20 of 59

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Photodynamic therapy of mild jaundice in babies (elevated bilirubin causes yellow skin pigmentation) turns bilirubin into more soluble form, easier to excrete from the body. What type of laser light is most suitable for skin treatment:

Select one of the following:

  • Red

  • Orange

  • Blue

Question 21 of 59

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In photo-dynamic therapy, malignant tissue is selectively destroyed by a combination of:

Select one of the following:

  • Photosensitizing drug (photosensitizer) and the presence of oxygen

  • Photosensitizer, sunlight and oxygen

  • Photosensitizer and laser light

Question 22 of 59

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Photodynamic therapy based on:

Select one of the following:

  • Existent singlet oxygen (1 O2) in cancer tissues

  • Singlet oxygen (1 O2) generation upon irradiation

  • Molecular oxygen (O2) generation upon irradiation

Question 23 of 59

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In a optical microscope the object is located at a distance

Select one of the following:

  • Less than the focal length of the objective lens

  • More than the focal length but less than double the focal length of objective

  • Exactly at the focal length of the objective lens

Question 24 of 59

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In an optical microscope, where is the object located with respect to the eyepiece lens:

Select one of the following:

  • Less than the focal distance of the eyepiece

  • Further than the focal distance, but less than double the focal distance of the eyepiece

  • At the focal distance of the eyepiece lens

Question 25 of 59

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The image formed by the microscope lens is:

Select one of the following:

  • Real

  • Virtual

  • Real and Reduced

Question 26 of 59

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The image formed by the microscope eyepiece is:

Select one of the following:

  • Real

  • Virtual

  • Real and Reduced

Question 27 of 59

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The image formed by a compound microscope is:

Select one of the following:

  • Real, Magnified and Reversed

  • Real, Magnified and Erect (upright)

  • Virtual, Magnified and Reversed

Question 28 of 59

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What feature of the human eye limits the maximum magnification of optical microscope:

Select one of the following:

  • The Optic Power

  • The Resolution

  • The Spectral Sensitivity

Question 29 of 59

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A negative magnification always means that the image is:

Select one of the following:

  • Erect

  • Real

  • Virtual

  • Inverted

Question 30 of 59

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UV microscopes do not have any significant applications in medicine despite their maximum useful magnification which is about 2 times higher than that of the conventional microscope because:

Select one of the following:

  • The image cannot be directly observed with the eyes

  • UV rays are dangerous

  • No powerful sources of UV light exist

  • UV rays change the objects under examination.

Question 31 of 59

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After passing through a convex lens, rays of light traveling parallel to the axis, will be refracted to the lens:

Select one of the following:

  • Center

  • Principle focus

  • Remain parallel

Question 32 of 59

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When an object is located at distance greater than two focal lengths in front of a converging lens, the image will be:

Select one of the following:

  • Real and Enlarged

  • Virtual and Enlarged

  • Real and Reduced

  • Virtual

Question 33 of 59

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Virtual images formed by converging lenses would appear:

Select one of the following:

  • Bigger

  • The Same Size

  • Smaller

Question 34 of 59

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What wave phenomenon allows the existence of optical microscopes:

Select one of the following:

  • Diffraction

  • Refraction

  • Interference

Question 35 of 59

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In an optical microscope, Wavelength of light is changed from 550 nm to 450 nm. The numerical aperture (NA) stays the same same. The resolution will:

Select one of the following:

  • Get better

  • Get worse

  • Stay the same

Question 36 of 59

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Electron microscopes have better resolution than light microscopes. This is because:

Select one of the following:

  • Electrons are faster than light

  • Electrons have more energy than light

  • Electrons have shorter wavelengths than light

Question 37 of 59

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Electron microscopes use special lenses such as:

Select one of the following:

  • Optical Lenses with high index of refraction

  • Optical Lenses with low index of refraction

  • Magnetic lenses

Question 38 of 59

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The human eye is most sensitive to:

Select one of the following:

  • Blue light

  • Green light

  • Red light

Question 39 of 59

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Which wavelength λ is not perceived by the human eye:

Select one of the following:

  • 500 nm

  • 1000 nm

  • 620 nm

Question 40 of 59

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The optical power of the human eye is approximately equal to:

Select one of the following:

  • 0.5 dpt

  • 7 dpt

  • 17 dpt

  • 70 dpt

Question 41 of 59

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2/3 of human eyes optical power is due to the air-cornea interface. This is because:

Select one of the following:

  • Refractive indices of air and cornea have greater difference, compared to other refractive surfaces in the eye.

  • The cornea has the largest curvature

  • The cornea is thicker than the lens

Question 42 of 59

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The image formed on the retina of the human eye is at a distance:

Select one of the following:

  • Greater than the double focal length of the eye's lens

  • Equal to the double focal length of the eye's lens

  • Less than the double focal length of the eye's lens

Question 43 of 59

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The image formed on the retina is:

Select one of the following:

  • Real, Enlarged and Inverted

  • Real, Reduced and Inverted

  • Real, Reduced and Erect

Question 44 of 59

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Nature has deprived human eyes from IR vision, which some animals poses. Is this expedient:

Select one of the following:

  • No. Human optical receptors are less adept.

  • No. Humans cannot hunt at night.

  • Yes, The eye is a powerful source of IR and will be blinded by self emission.

Question 45 of 59

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Can you tell by looking at a person's eyes and spectacles, if they have myopia or hyperopia? Which of the statements below is not correct?

Select one of the following:

  • Myopic eyes look semi-closed and hyperopic eyes look wide open

  • Myopic lenses have thicker periphery, hyperopic have thicker center part

  • Pupils of myopic eyes look small and pupils of hyperopic eyes look enlarged.

Question 46 of 59

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Which human organ is "responsible" for inter-eye coordination:

Select one of the following:

  • The thyroid gland

  • The vestibular apparatus

  • The brain

Question 47 of 59

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Astigmatism is due to:

Select one of the following:

  • Non-uniform curvature of eye lens:

  • Lack of coincidence of eye's anatomical and optical exes

  • Non-uniform curvature of the cornea

Question 48 of 59

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The stroboscopic effect is due to:

Select one of the following:

  • The ability of the optical receptor to retain images for certain time

  • The ability of the optical receptor to determine the distances by eye (the so called estimation by sight)

  • The volumetric (three-dimensional) vision.

Question 49 of 59

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What type of lenses are used for correction of myopia (short-sightedness)

Select one of the following:

  • Cylindrical

  • Spherical, Diverging

  • Spherical, Converging

Question 50 of 59

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What type of lenses are used for correction of hypermetropia (far-sightness)

Select one of the following:

  • Spherical, Diverging

  • Spherical, Converging

  • Cylindrical

Question 51 of 59

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What type of lenses are used for correction of astigmatism:

Select one of the following:

  • Sphero-cylindrical

  • Cylindrical

  • Spherical, Diverging

Question 52 of 59

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Snell's window is an underwater phenomenon where a submerged observer looking up could see the entire hemisphere, horizon to horizon. In this case, a 180 degree view above water is compressed into a 97 degree angle under water (Figure 10, not included). This is possible because:

Select one of the following:

  • Fish eyes are rounder than human eyes

  • The water surface is curved

  • Sound travels faster in water than in air

  • Light travels faster in air then in water

Question 53 of 59

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Fish eyes are remarkably similar to human eyes. One significant different is the shape of crystalline lens. In fish they are denser and more spherical. This adaptation can be contributed to:

Select one of the following:

  • The higher pressure underwater

  • The speed of light in water

  • The need to collect light from wider angles

Question 54 of 59

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The following can be described as refractive disorders of the eye:

Select one of the following:

  • Myopia, Hyperopia, Strabismus

  • Myopia, Hyperopia, Astigmatism

  • Myopia, Presbyopia, Colour blindness

  • Answers A + B

Question 55 of 59

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Underwater vision (for humans) is blurry. The focusing power of the cornea is greatly reduced when in contact with water. Why is that? :

Select one of the following:

  • Because of additional pressure from water molecules

  • Index of refraction of water is greater than index of refraction of air.

  • Index of refraction of water is similar to the index of refraction of the cornea.

Question 56 of 59

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Which statement describes correctly the photoreceptor cells of the retina

Select one of the following:

  • Cones have better sensitivity but lower resolution than rods

  • Rods have better sensitivity but a lower count then cones

  • Cones have higher resolution but lower sensitivity than rods.

Question 57 of 59

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There are three types of colour sensitive cone cells in the retina. Two types overlap significantly in their spectral sensitivity and one does not overlap much with the other two. Which are the two overlapping colours?

Select one of the following:

  • Blue and green

  • Red and blue

  • Green and Red

Question 58 of 59

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Human eyes are the most sensitive to green light at 550 nm wavelength. What is the best explanation for this adaption:

Select one of the following:

  • Green light is between the red and the blue

  • Green light is usually brighter than red

  • Green light from the sun arrives in greater intensity.

Question 59 of 59

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In addition to their eyes, Rattlesnakes have a pair of sensory organs called "Pits". Pits have a short range and are used mostly in night hunting. What type of waves can pits detect?

Select one of the following:

  • Ultrasound

  • Ultraviolet

  • Infrasound

  • Infrared

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PMU - Year 1 Physics - Part 3(B)

Sole C
Quiz by , created almost 2 years ago

All Questions uploaded word for word from MCQ book. All Credit to Authors. Mistakes due in process may have been made, use and check your work at your own discretion. Only simple writing allowed, i.e Superscript and Subscript absent. Questions missed due to Figure/Diagrams/Text: 69.89.90.106.

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Sole C
Created by Sole C almost 2 years ago
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