Sole C
Quiz por , criado more than 1 year 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.

129
6
0
Sole C
Criado por Sole C mais de 9 anos atrás
Fechar

PMU - Year 1 Physics - Part 3(B)

Questão 1 de 59

1

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

Selecione uma das seguintes:

  • λ1 < λ2;

  • λ1 > λ2

  • λ1 = λ2

Explicação

Questão 2 de 59

1

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

Selecione uma das seguintes:

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

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

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

Explicação

Questão 3 de 59

1

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

Selecione uma das seguintes:

  • Singlet

  • Triplet (metastable)

  • Energy level higher than ground level.

Explicação

Questão 4 de 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:

Selecione uma das seguintes:

  • Emission of white light

  • Stimulated emission

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

Explicação

Questão 5 de 59

1

The active medium of a laser must have:

Selecione uma das seguintes:

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

  • Acoustic impedance Za matching that of target tissues

  • The possibility for population inversion

Explicação

Questão 6 de 59

1

Light is monochromatic when:

Selecione uma das seguintes:

  • It is a single wavelength λ

  • It propagates in the same direction

  • It propagates in-phase

Explicação

Questão 7 de 59

1

The output mirror of laser resonator is:

Selecione uma das seguintes:

  • Semi-transparent

  • Completely transparent

  • Non-transparent (opaque)

Explicação

Questão 8 de 59

1

The laser can be:

Selecione uma das seguintes:

  • A flux of protons

  • A flux of electrons with the same energy

  • An electromagnetic radiation with specific properties

Explicação

Questão 9 de 59

1

The laser is:

Selecione uma das seguintes:

  • Radionuclide generator for generating metastable radionuclide 99m Tc

  • Generator of light with specific properties

  • Ultrasound generator

Explicação

Questão 10 de 59

1

Light generation in a laser is a result of:

Selecione uma das seguintes:

  • Spontaneous electron transitions

  • Stimulated electron transitions

  • Spontaneous and stimulated transitions of electrons

Explicação

Questão 11 de 59

1

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

Selecione uma das seguintes:

  • Denaturation of proteins

  • Coagulation

  • Photoablation

Explicação

Questão 12 de 59

1

Electromagnetic waves are coherent when:

Selecione uma das seguintes:

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

  • They have the same wavelength λ

  • They propagate in the same plane.

Explicação

Questão 13 de 59

1

What is the definition for population inversion?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 14 de 59

1

Laser radiation DOES NOT have the properties of:

Selecione uma das seguintes:

  • Coherence and polarization

  • Emission in the visible spectrum only

  • Collimation (Directionality)

Explicação

Questão 15 de 59

1

What properties summarize laser light the best:

Selecione uma das seguintes:

  • Monochromatic, Coherent, Collimated

  • Polychromatic, Polarized, Collimated

  • Monochromatic, Coherent, Diffracted

Explicação

Questão 16 de 59

1

Lasers produce light with specific properties through:

Selecione uma das seguintes:

  • Spontaneous emission

  • Stimulated emission

  • Fluorescence

Explicação

Questão 17 de 59

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 18 de 59

1

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

Selecione uma das seguintes:

  • UV Range

  • IR Range

  • Visible Range

Explicação

Questão 19 de 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:

Selecione uma das seguintes:

  • λ = 390 nm

  • λ = 500 nm

  • λ = 630 nm

Explicação

Questão 20 de 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:

Selecione uma das seguintes:

  • Red

  • Orange

  • Blue

Explicação

Questão 21 de 59

1

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

Selecione uma das seguintes:

  • Photosensitizing drug (photosensitizer) and the presence of oxygen

  • Photosensitizer, sunlight and oxygen

  • Photosensitizer and laser light

Explicação

Questão 22 de 59

1

Photodynamic therapy based on:

Selecione uma das seguintes:

  • Existent singlet oxygen (1 O2) in cancer tissues

  • Singlet oxygen (1 O2) generation upon irradiation

  • Molecular oxygen (O2) generation upon irradiation

Explicação

Questão 23 de 59

1

In a optical microscope the object is located at a distance

Selecione uma das seguintes:

  • 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

Explicação

Questão 24 de 59

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 25 de 59

1

The image formed by the microscope lens is:

Selecione uma das seguintes:

  • Real

  • Virtual

  • Real and Reduced

Explicação

Questão 26 de 59

1

The image formed by the microscope eyepiece is:

Selecione uma das seguintes:

  • Real

  • Virtual

  • Real and Reduced

Explicação

Questão 27 de 59

1

The image formed by a compound microscope is:

Selecione uma das seguintes:

  • Real, Magnified and Reversed

  • Real, Magnified and Erect (upright)

  • Virtual, Magnified and Reversed

Explicação

Questão 28 de 59

1

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

Selecione uma das seguintes:

  • The Optic Power

  • The Resolution

  • The Spectral Sensitivity

Explicação

Questão 29 de 59

1

A negative magnification always means that the image is:

Selecione uma das seguintes:

  • Erect

  • Real

  • Virtual

  • Inverted

Explicação

Questão 30 de 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:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 31 de 59

1

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

Selecione uma das seguintes:

  • Center

  • Principle focus

  • Remain parallel

Explicação

Questão 32 de 59

1

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

Selecione uma das seguintes:

  • Real and Enlarged

  • Virtual and Enlarged

  • Real and Reduced

  • Virtual

Explicação

Questão 33 de 59

1

Virtual images formed by converging lenses would appear:

Selecione uma das seguintes:

  • Bigger

  • The Same Size

  • Smaller

Explicação

Questão 34 de 59

1

What wave phenomenon allows the existence of optical microscopes:

Selecione uma das seguintes:

  • Diffraction

  • Refraction

  • Interference

Explicação

Questão 35 de 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:

Selecione uma das seguintes:

  • Get better

  • Get worse

  • Stay the same

Explicação

Questão 36 de 59

1

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

Selecione uma das seguintes:

  • Electrons are faster than light

  • Electrons have more energy than light

  • Electrons have shorter wavelengths than light

Explicação

Questão 37 de 59

1

Electron microscopes use special lenses such as:

Selecione uma das seguintes:

  • Optical Lenses with high index of refraction

  • Optical Lenses with low index of refraction

  • Magnetic lenses

Explicação

Questão 38 de 59

1

The human eye is most sensitive to:

Selecione uma das seguintes:

  • Blue light

  • Green light

  • Red light

Explicação

Questão 39 de 59

1

Which wavelength λ is not perceived by the human eye:

Selecione uma das seguintes:

  • 500 nm

  • 1000 nm

  • 620 nm

Explicação

Questão 40 de 59

1

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

Selecione uma das seguintes:

  • 0.5 dpt

  • 7 dpt

  • 17 dpt

  • 70 dpt

Explicação

Questão 41 de 59

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 42 de 59

1

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

Selecione uma das seguintes:

  • 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

Explicação

Questão 43 de 59

1

The image formed on the retina is:

Selecione uma das seguintes:

  • Real, Enlarged and Inverted

  • Real, Reduced and Inverted

  • Real, Reduced and Erect

Explicação

Questão 44 de 59

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 45 de 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?

Selecione uma das seguintes:

  • 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.

Explicação

Questão 46 de 59

1

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

Selecione uma das seguintes:

  • The thyroid gland

  • The vestibular apparatus

  • The brain

Explicação

Questão 47 de 59

1

Astigmatism is due to:

Selecione uma das seguintes:

  • Non-uniform curvature of eye lens:

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

  • Non-uniform curvature of the cornea

Explicação

Questão 48 de 59

1

The stroboscopic effect is due to:

Selecione uma das seguintes:

  • 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.

Explicação

Questão 49 de 59

1

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

Selecione uma das seguintes:

  • Cylindrical

  • Spherical, Diverging

  • Spherical, Converging

Explicação

Questão 50 de 59

1

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

Selecione uma das seguintes:

  • Spherical, Diverging

  • Spherical, Converging

  • Cylindrical

Explicação

Questão 51 de 59

1

What type of lenses are used for correction of astigmatism:

Selecione uma das seguintes:

  • Sphero-cylindrical

  • Cylindrical

  • Spherical, Diverging

Explicação

Questão 52 de 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:

Selecione uma das seguintes:

  • 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

Explicação

Questão 53 de 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:

Selecione uma das seguintes:

  • The higher pressure underwater

  • The speed of light in water

  • The need to collect light from wider angles

Explicação

Questão 54 de 59

1

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

Selecione uma das seguintes:

  • Myopia, Hyperopia, Strabismus

  • Myopia, Hyperopia, Astigmatism

  • Myopia, Presbyopia, Colour blindness

  • Answers A + B

Explicação

Questão 55 de 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? :

Selecione uma das seguintes:

  • 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.

Explicação

Questão 56 de 59

1

Which statement describes correctly the photoreceptor cells of the retina

Selecione uma das seguintes:

  • 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.

Explicação

Questão 57 de 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?

Selecione uma das seguintes:

  • Blue and green

  • Red and blue

  • Green and Red

Explicação

Questão 58 de 59

1

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

Selecione uma das seguintes:

  • 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.

Explicação

Questão 59 de 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?

Selecione uma das seguintes:

  • Ultrasound

  • Ultraviolet

  • Infrasound

  • Infrared

Explicação