CBSE Questions for Class 12 Medical Physics Ray Optics And Optical Instruments Quiz 5 - MCQExams.com

Match column I with column II and select the correct answer using the codes given below:
  Column I  Column II
 (A) Myopia (p) The power of accommodation of the eye decreases with ageing 
 (B) Hypermetropia (q) The focal length of the eye lens is too long 
 (C) Presbyopia (r) The focal length of the eye lens is too small
 (D) Astigmatism (s) The eyes fail to distinguish horizontal and vertical lines at the same distance 
  • (A) $$\rightarrow$$ r, (B) $$\rightarrow$$ q, (C) $$\rightarrow$$ p, (D) $$\rightarrow$$ s
  • (A) $$\rightarrow$$ p, (B) $$\rightarrow$$ r, (C) $$\rightarrow$$ s, (D) $$\rightarrow$$ q
  • (A) $$\rightarrow$$ s, (B) $$\rightarrow$$ p, (C) $$\rightarrow$$ r, (D) $$\rightarrow$$ q
  • (A) $$\rightarrow$$ q, (B) $$\rightarrow$$ r, (C) $$\rightarrow$$ p, (D) $$\rightarrow$$ s
The light enters our eye through the transparent _________, passes through the _______ and is focused on the _______. The ________ is sensitive to light and sends images to our brain through  _________ . 
  • cornea, lens, retina, retina, optic nerve
  • retina,cornea, lens, retina, optic nerve
  • retina, cornea, lens, optic nerve ,retina
  • cornea,retina, lens, retina, optic nerve
Fill in the blanks:
In our eyes an image of objects we wish to view is made at the _________ .
  • retina
  • pupil
  • iris
  • cornea
A coin kept in a container and not visible can be viewed by pouring water into the container. It happens because of the 
  • Reflection of light.
  • Refraction of light.
  • Variable refractive index of water.
  • None of the above.
Blue colour of sky is due to :
  • dispersion of light
  • scattering of light
  • reflection of light
  • refraction of light
A telescope gives an .............. (inverted / erect) and ........ (enlarged/diminished) image of a distant object. Choose the correct alternative.
  • Inverted, diminished
  • Inverted, enlarged
  • Erect, diminished
  • Erect, enlarged
Select the correct alternative
The angle between the normal and refracted ray is called :
  • angle of deviation
  • angle of incidence
  • angle of refraction
  • none of these
A spectrum is obtained by sending a beam of white light through a prism. A second prism exactly similar to the first one is placed in an inverted position with the sides parallel to the first. Now
  • A new spectrum will be formed on the screen with double the number of colours present in the previous spectrum
  • New spectrum will be obtained on the screen with only half the number of colours present in the previous spectrum
  • Previous spectrum will disappear and we will obtain a white light formed by the fusion of the colours
  • A spectrum with same number of colours present in the previous spectrum will be formed but their wave lengths will be increased twice
Is the color of emergent beam X white light:

282587_a06ab2d36a504298a42069014a153900.png
  • True
  • False
A liquid of refractive index 1.6 is introduced between two identical plano-convex lens in two ways P and Q as shown. If the lens material has refractive index 1.5, the combination is
1075407_44762837aaac42f1ab2d13218548d2fa.PNG
  • converging in both P and Q
  • diverging in both P and Q
  • converging in Q only
  • converging in P only
.......... happens when a wave passes from one medium to another at an angle.
  • Refraction
  • Reflection
  • Dispersion
  • Scattering
Identify the part "B" from the shown figure of human eye :
283834_56dcb41f73b347b19257dc177f04500a.png
  • Retina
  • Iris
  • Cornea 
  • Pupil
Which part of human eye controls the amount of light entering the eye?
  • Cornea
  • Retina
  • Pupil
  • Iris
Two identical prism PQR and P' Q' R' are given. White light is passed through PQR as shown in fig.
Which of the following position of P' Q' R' will again yield white light ?
283794_7bea09b8a4df4ac2a4d21b404a39c93a.png
  • None of these
State whether true or false :
Both the telescope and compound microscope make use of two lenses-one concave and one convex.
  • True
  • False
With age 'Near point' and 'Far point' recedes due to
A. Weakening of ciliary muscles
B. decreasing ability to change the focal length
  • A is correct
  • B is correct
  • Both A and B are correct
  • Neither A nor B is correct
A student has difficulty in reading the blackboard while sitting in the last row. From the given options, choose the defect child is suffering from and its correction measures :
  • Defect: Myopia
    Correction: Concave lens of suitable focal length
  • Defect: Hypermetropia
    Correction: Convex lens of suitable focal length
  • Defect: Myopia
    Correction: Medicines
  • Defect: Hypermetropia
    Correction: Medicines
Sometimes, a person suffers from both the defects, myopia and hypermetropia. Which of the following is used to correct this defect?
  • Convex lens
  • Concave lens
  • Bifocal lens
  • Cylindrical lens
Identify the defect in the eye shown in the figure.
283860.png
  • Hypermetropia
  • Myopia
  • Astigmatism
  • Night blindness
A person who is nearsighted will have the most trouble in reading:
  • A computer screen in front of him or her
  • A book in his or her hands
  • A street sign across the street
  • The title of a pamphlet on a nearby table
What is the name of the circular aperture through which light enters the eye ?
  • Iris
  • Pupil
  • Cornea
  • Optic Nerve
Telescopes use concave mirror
  • True
  • False
The figure illustrates correction of vision for a certain defect of human eye. Identify the defect which is corrected here.

283868_605191ae74004c5eaa12adb44b5a47fe.png
  • Myopia
  • Hypermetropia
  • Astigmatism
  • Nigh Blindness
What is the function of the iris in human eye ?
  • Iris  restricts the light to pass through the eye over to the retina.
  • Iris provides protection to the eye from microorganisms.
  • Iris controls the size of the pupil and hence the amount of light entering the eye.
  • Iris allows colour detection in eye.
Identify the defect which is corrected in the attached figure.
283865.png
  • Hypermetropia
  • Myopia
  • Astigmatism
  • Night Blindness
What type of lens from the following would you have in your magnifying lens to read a page in small print ?
  • A convex lens of focal length 80 cm
  • A concave lens of focal length 80 cm
  • A concave lens of focal length 4 cm
  • A convex lens of focal length of 4 cm
A simple telescope has
  • A convex lens and a concave lens
  • A concave mirror and a convex lens
  • Two convex lenses
  • Two concave lenses
Which of the following  lenses would you prefer to use while reading small letters found in a dictionary ?
  • A convex lens of focal length 50 cm
  • A concave lens of focal length 50 cm
  • A convex lens of focal length 5 cm
  • A concave lens of focal length 5 cm
A vision problem that happens when light is focussed in front of the retina is:
  • Farsightedness
  • Nearsightedness
  • Colour deficiency
  • None of these
A man cannot see objects distinctly at a distance less than 1 metre. He is suffering from 
  • Old age sight
  • Short-sightedness
  • Long-sightedness
  • Opaqueness of the lens
Match List-I with List- II and select the answer using the codes given below the lists:

List-IList-II
A.Microscope1.To see objects on the surface by an observer in a trench
B.Telescope2.To see small objects
C.Periscope3.To see distant objects
D.Camera4.To take photographs of objects
  • $$2\, \quad\, 1\, \quad\, 4\, \quad\, 3$$
  • $$1\, \quad\, 2\, \quad\, 3\, \quad\, 4$$
  • $$2\, \quad\, 3\, \quad\, 4\, \quad\, 1$$
  • $$2\, \quad\, 3\, \quad\, 1\, \quad\, 4$$
A number of thin prism of prism angle $$A$$ and refractive index $$\mu$$ are arranged on periphery of circle such that any light ray entering from one prism move along a regular polygon
  • number of prism used will be $$\cfrac { 4\pi }{ (\mu -1)A } $$
  • If $$A$$ is rational, $$\mu$$ must be rational
  • if $$A$$ is rational, $$\mu$$ must be irrational
  • If $$A$$ is irrational, $$\mu$$ must be irrational
The focal length of eye lens and object lens of a telescope is 4 mm and 4 cm respectively. If final image of an far object is at $$\displaystyle \infty $$. Then the magnifying power and length of the tube are:
  • 10, 4.4 cm
  • 4, 44 cm
  • 44, 10 cm
  • 10, 44 cm

If a person cannot see an object clearly when it is placed at about 25 cm away from him, he is suffering from:

  • Mypoia
  • Hypermetropia
  • Astigmatism
  • Presbyopia
  • None of these
The size of the pupil is controlled by the iris.
  • True
  • False
Two equilateral prisms are arranged as shown in figure such that a ray of white light is incident at point X The ray of light which emerges out of the prism Q
314590.png
  • Will show all the colours of spectrum
  • Will be white light
  • Will be orange in colour
  • Will be dull white in colour
Fill in the blanks:
An aged person suffering from __________, caused by the weak accommodation power of the eye lens associated with old age, should wear _________ lenses.

  • Myopia, concave 
  • Hypermetropia, convex
  • Presbyopia, bifocal
  • Astigmastism, cylindrical
An under-water swimmer cannot see very clearly even in absolutely clear water because of:
  • Absorption of light in water
  • Scattering of light in water
  • Reduction of speed of light in water
  • Change in the focal length of eye lens.
At the junction of the optic nerve and the retina, there are no sensory cells, so no vision is possible at that spot. This is called the blind spot.
  • True
  • False
Four convex lenses A B, C and D have focal lengths of 5 cm, 5 m, 50 cm and 15 cm respectively.Which one would you choose as a magnifying glass?
  • A
  • B
  • C
  • D
The focal length of eye lens and object lens of a telescope is 4 mm and 4 cm respectively. If final image of an far object is at $$\infty $$. Then the magnifying power and length of the tube are :
  • 10, 4.4 cm
  • 4, 44 cm
  • 44,10 cm
  • 10, 44 cm
Refraction of light in the eye occurs at
  • The pupil only
  • The cornea only
  • The lens only
  • Both the cornea and the lens
Which of the following does not represent correct refraction?
A person is not able to see nearby objects clearly. His vision can be corrected with the help of spectacles containing:
  • Converging lenses
  • Diverging lenses
  • Plane lenses
  • Prismatic lenses
Occurrence of mirage in deserts in summer is an example of ..........................
  • reflection of light
  • refraction of light
  • propagation of sound
  • conduction of heat
The defect of vision which cannot be corrected with the help of spectacles is:
  • Cataract
  • Presbyopia
  • Myopia
  • Hypermetropia
A child was prescribed the following lenses for his spectacles by the optician:Left eye: + 2.50D, Right eye: +1.25D .The child has a defect of vision called:
  • Presbyopia
  • Myopia
  • Hypermetropia
  • Astigmatism
If the optician's prescription for the spectacles reads: Left eye: -3.00 D, Right eye: -3.5 D then the person is suffering from the defect of vision called:
  • Astigmatism
  • Myopia
  • Presbyopia
  • Hypermetropia
Which one of the following statements is correct?
  • The planets twinkle at night due to atmospheric refraction of light
  • The stars appear higher in the sky than they actually are, due to scattering of light
  • The blue colour of sky is due to scattering of light
  • The rainbow is produced by the reflection of white sunlight by water drops in the atmosphere.
Light enters an isosceles right triangular prism at normal incidence through face AB and undergoes total internal reflection at face BC as shown below :
The minimum value of the refractive index of the prifsm is close to:

333188_bc5b1bbb3e544fd6b4fc6d51c525d918.png
  • $$1.10$$
  • $$1.55$$
  • $$1.42$$
  • $$1.72$$
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