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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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PMU - Year 1 Physics - Part 3(B)

Frage 1 von 59

1

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

Wähle eine der folgenden:

  • λ1 < λ2;

  • λ1 > λ2

  • λ1 = λ2

Erklärung

Frage 2 von 59

1

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

Wähle eine der folgenden:

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

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

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

Erklärung

Frage 3 von 59

1

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

Wähle eine der folgenden:

  • Singlet

  • Triplet (metastable)

  • Energy level higher than ground level.

Erklärung

Frage 4 von 59

1

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

Wähle eine der folgenden:

  • Emission of white light

  • Stimulated emission

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

Erklärung

Frage 5 von 59

1

The active medium of a laser must have:

Wähle eine der folgenden:

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

  • Acoustic impedance Za matching that of target tissues

  • The possibility for population inversion

Erklärung

Frage 6 von 59

1

Light is monochromatic when:

Wähle eine der folgenden:

  • It is a single wavelength λ

  • It propagates in the same direction

  • It propagates in-phase

Erklärung

Frage 7 von 59

1

The output mirror of laser resonator is:

Wähle eine der folgenden:

  • Semi-transparent

  • Completely transparent

  • Non-transparent (opaque)

Erklärung

Frage 8 von 59

1

The laser can be:

Wähle eine der folgenden:

  • A flux of protons

  • A flux of electrons with the same energy

  • An electromagnetic radiation with specific properties

Erklärung

Frage 9 von 59

1

The laser is:

Wähle eine der folgenden:

  • Radionuclide generator for generating metastable radionuclide 99m Tc

  • Generator of light with specific properties

  • Ultrasound generator

Erklärung

Frage 10 von 59

1

Light generation in a laser is a result of:

Wähle eine der folgenden:

  • Spontaneous electron transitions

  • Stimulated electron transitions

  • Spontaneous and stimulated transitions of electrons

Erklärung

Frage 11 von 59

1

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

Wähle eine der folgenden:

  • Denaturation of proteins

  • Coagulation

  • Photoablation

Erklärung

Frage 12 von 59

1

Electromagnetic waves are coherent when:

Wähle eine der folgenden:

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

  • They have the same wavelength λ

  • They propagate in the same plane.

Erklärung

Frage 13 von 59

1

What is the definition for population inversion?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 14 von 59

1

Laser radiation DOES NOT have the properties of:

Wähle eine der folgenden:

  • Coherence and polarization

  • Emission in the visible spectrum only

  • Collimation (Directionality)

Erklärung

Frage 15 von 59

1

What properties summarize laser light the best:

Wähle eine der folgenden:

  • Monochromatic, Coherent, Collimated

  • Polychromatic, Polarized, Collimated

  • Monochromatic, Coherent, Diffracted

Erklärung

Frage 16 von 59

1

Lasers produce light with specific properties through:

Wähle eine der folgenden:

  • Spontaneous emission

  • Stimulated emission

  • Fluorescence

Erklärung

Frage 17 von 59

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 18 von 59

1

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

Wähle eine der folgenden:

  • UV Range

  • IR Range

  • Visible Range

Erklärung

Frage 19 von 59

1

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:

Wähle eine der folgenden:

  • λ = 390 nm

  • λ = 500 nm

  • λ = 630 nm

Erklärung

Frage 20 von 59

1

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:

Wähle eine der folgenden:

  • Red

  • Orange

  • Blue

Erklärung

Frage 21 von 59

1

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

Wähle eine der folgenden:

  • Photosensitizing drug (photosensitizer) and the presence of oxygen

  • Photosensitizer, sunlight and oxygen

  • Photosensitizer and laser light

Erklärung

Frage 22 von 59

1

Photodynamic therapy based on:

Wähle eine der folgenden:

  • Existent singlet oxygen (1 O2) in cancer tissues

  • Singlet oxygen (1 O2) generation upon irradiation

  • Molecular oxygen (O2) generation upon irradiation

Erklärung

Frage 23 von 59

1

In a optical microscope the object is located at a distance

Wähle eine der folgenden:

  • 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

Erklärung

Frage 24 von 59

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 25 von 59

1

The image formed by the microscope lens is:

Wähle eine der folgenden:

  • Real

  • Virtual

  • Real and Reduced

Erklärung

Frage 26 von 59

1

The image formed by the microscope eyepiece is:

Wähle eine der folgenden:

  • Real

  • Virtual

  • Real and Reduced

Erklärung

Frage 27 von 59

1

The image formed by a compound microscope is:

Wähle eine der folgenden:

  • Real, Magnified and Reversed

  • Real, Magnified and Erect (upright)

  • Virtual, Magnified and Reversed

Erklärung

Frage 28 von 59

1

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

Wähle eine der folgenden:

  • The Optic Power

  • The Resolution

  • The Spectral Sensitivity

Erklärung

Frage 29 von 59

1

A negative magnification always means that the image is:

Wähle eine der folgenden:

  • Erect

  • Real

  • Virtual

  • Inverted

Erklärung

Frage 30 von 59

1

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:

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 31 von 59

1

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

Wähle eine der folgenden:

  • Center

  • Principle focus

  • Remain parallel

Erklärung

Frage 32 von 59

1

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

Wähle eine der folgenden:

  • Real and Enlarged

  • Virtual and Enlarged

  • Real and Reduced

  • Virtual

Erklärung

Frage 33 von 59

1

Virtual images formed by converging lenses would appear:

Wähle eine der folgenden:

  • Bigger

  • The Same Size

  • Smaller

Erklärung

Frage 34 von 59

1

What wave phenomenon allows the existence of optical microscopes:

Wähle eine der folgenden:

  • Diffraction

  • Refraction

  • Interference

Erklärung

Frage 35 von 59

1

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:

Wähle eine der folgenden:

  • Get better

  • Get worse

  • Stay the same

Erklärung

Frage 36 von 59

1

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

Wähle eine der folgenden:

  • Electrons are faster than light

  • Electrons have more energy than light

  • Electrons have shorter wavelengths than light

Erklärung

Frage 37 von 59

1

Electron microscopes use special lenses such as:

Wähle eine der folgenden:

  • Optical Lenses with high index of refraction

  • Optical Lenses with low index of refraction

  • Magnetic lenses

Erklärung

Frage 38 von 59

1

The human eye is most sensitive to:

Wähle eine der folgenden:

  • Blue light

  • Green light

  • Red light

Erklärung

Frage 39 von 59

1

Which wavelength λ is not perceived by the human eye:

Wähle eine der folgenden:

  • 500 nm

  • 1000 nm

  • 620 nm

Erklärung

Frage 40 von 59

1

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

Wähle eine der folgenden:

  • 0.5 dpt

  • 7 dpt

  • 17 dpt

  • 70 dpt

Erklärung

Frage 41 von 59

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 42 von 59

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 43 von 59

1

The image formed on the retina is:

Wähle eine der folgenden:

  • Real, Enlarged and Inverted

  • Real, Reduced and Inverted

  • Real, Reduced and Erect

Erklärung

Frage 44 von 59

1

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

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 45 von 59

1

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?

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 46 von 59

1

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

Wähle eine der folgenden:

  • The thyroid gland

  • The vestibular apparatus

  • The brain

Erklärung

Frage 47 von 59

1

Astigmatism is due to:

Wähle eine der folgenden:

  • Non-uniform curvature of eye lens:

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

  • Non-uniform curvature of the cornea

Erklärung

Frage 48 von 59

1

The stroboscopic effect is due to:

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 49 von 59

1

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

Wähle eine der folgenden:

  • Cylindrical

  • Spherical, Diverging

  • Spherical, Converging

Erklärung

Frage 50 von 59

1

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

Wähle eine der folgenden:

  • Spherical, Diverging

  • Spherical, Converging

  • Cylindrical

Erklärung

Frage 51 von 59

1

What type of lenses are used for correction of astigmatism:

Wähle eine der folgenden:

  • Sphero-cylindrical

  • Cylindrical

  • Spherical, Diverging

Erklärung

Frage 52 von 59

1

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:

Wähle eine der folgenden:

  • 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

Erklärung

Frage 53 von 59

1

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:

Wähle eine der folgenden:

  • The higher pressure underwater

  • The speed of light in water

  • The need to collect light from wider angles

Erklärung

Frage 54 von 59

1

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

Wähle eine der folgenden:

  • Myopia, Hyperopia, Strabismus

  • Myopia, Hyperopia, Astigmatism

  • Myopia, Presbyopia, Colour blindness

  • Answers A + B

Erklärung

Frage 55 von 59

1

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

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 56 von 59

1

Which statement describes correctly the photoreceptor cells of the retina

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 57 von 59

1

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?

Wähle eine der folgenden:

  • Blue and green

  • Red and blue

  • Green and Red

Erklärung

Frage 58 von 59

1

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

Wähle eine der folgenden:

  • 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.

Erklärung

Frage 59 von 59

1

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?

Wähle eine der folgenden:

  • Ultrasound

  • Ultraviolet

  • Infrasound

  • Infrared

Erklärung