Self Studies
Self Studies
Self Studies
Self Studies
Selfstudy
Selfstudy

Human Eye and Colourful World Test - 37

Result Self Studies

Human Eye and Colourful World Test - 37
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0
    The near point of a long sighted person is 40 cm from the eye. To read a book held at a distance of 25 cm, he will need spectacles containing 
    Solution
    $$Answer:-$$ D option
    Long sightedness means converging power of eye lens has decreased so to increase converging power converging lens or convex lens is needed. 
    By using convex lens we are focussing image to be formed at retina ,earlier due to long sightedness near point was shifted to 40 cm but by using convex lens it is now shifted to 25cm

  • Question 2
    1 / -0
    A man can read the number of a distant bus clearly but is not able to read a book clearly. Which defect of the eye is he suffering from?
    Solution
    $$Answer:-$$ B option
    In this defect near point is shifted at a distance, person suffering from it is able to see distant things clearly but unable to see near objects. This defect is called hypermetropia.

  • Question 3
    1 / -0
    The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect?
    Solution

    $$Answer:-$$ C option

    In the problem, it is given that the near point of defective eye is 1 m and that of a normal eye is 25 cm. Hence $$u = -25$$ cm. The lens used forms its virtual image at near point of hypermetropic eye i.e., $$v = - 1 m = -100$$ cm. 

    Using lens formula, we have :-

    $$\dfrac { 1 }{ v } -\dfrac { 1 }{ u } =\dfrac { 1 }{ f } \\ \dfrac { 1 }{ -100 } -\dfrac { 1 }{ -25 } =\dfrac { 1 }{ f } \\ f=\dfrac { 100 }{ 3 } =0.33\quad m\\ power=\dfrac { 1 }{ f(in\quad metres) } =+3.0\quad D$$

  • Question 4
    1 / -0
    Refraction of light in the eye occurs at
    Solution
    Refraction of light in the eye occurs at both the cornea and the lens.
    Like a camera, the human eye focuses light to produce sharp images. Light rays reflecting from distant objects are focused on the retina after they passed through the cornea.
  • Question 5
    1 / -0
    Mirages are observed in atmosphere due to the phenomenon of:
    Solution
    A mirage is a naturally-occurring optical phenomenon, in which light rays are bent to produce a displaced image of distant objects or the sky. The principal physical cause of a mirage is total internal reflection. It is depicted in the figure.
    Hence, option B is correct.

  • Question 6
    1 / -0
    A person is not able to see nearby objects clearly. His vision can be corrected with the help of spectacles containing:
    Solution
    If a person cannot see the nearby objects clearly this means the image of object is formed behind the retina.
    So we have to converge these light rays coming from object and focus these rays on retina of eye by using Converging(Convex) Lenses.

  • Question 7
    1 / -0
    The defect of vision which cannot be corrected with the help of spectacles is:
    Solution
    Cataract disease cannot be corrected with the help of spectacles.

    A cataract is a clouding of the lens in the eye leading to a decrease in vision. It can affect one or both eyes. Often it develops slowly. 
    Cataracts are most commonly due to ageing but may also occur due to trauma or radiation exposure, be present from birth, or occur following eye surgery for other problems.
     
    Option A is correct.

  • Question 8
    1 / -0
    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:
    Solution
    The prescribed spectacles are of positive power which means the lenses are convex (converging). 
    The convex lens is used when a person cannot see the nearby objects clearly because the image received by the eye is focused behind the retina.
    This disease is called hypermetropia and is also known as far-sightedness.

  • Question 9
    1 / -0
    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:
    Solution
    The prescribed spectacles are of negative power which means the lenses are concave (diverging). 
    The concave lens is used when a person cannot see the distant objects clearly because the image received by the eye is focused in front of the retina.
    This disease is called myopia and also known as Near-sightedness.
  • Question 10
    1 / -0
    Which one of the following statements is correct?
    Solution

    The blue colour of the sky is due to the scattering of light by small particles of the atmosphere (air molecules). When white light (from the sun) enters the earth's atmosphere, it gets scattered away due to the atmospheric particles. Since blue colour has the minimum wavelength, so blue colour scatters the most and thus the sky appears blue.

Self Studies
User
Question Analysis

  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now