Self Studies
Self Studies
Self Studies
Self Studies

Human Eye and Colourful World Test - 58

Result Self Studies

Human Eye and Colourful World Test - 58
  • 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
    Stars are not visible in the day time because
    Solution
    During the night time the sunlight doesn't complete reach the part of earth we are residing in. Hence, the sky is darker compared to day time. So, the visibility of the stars increases and we can see them properly.
    During the day time, the sunlight reaches the part of earth we are residing in directly. The particles present in the atmosphere causes the phenomenon of atmospheric scattering which causes the sunlight to scatter brightly across the sky. This brightness are so high that the light emitted by the stars are completely covered by the sunlight. Hence, we cannot see the stars in daytime. 
    $$\therefore$$ our correct answer is option (D).
  • Question 2
    1 / -0
    The sky would appear red instead of blue if
    Solution
    The Colour of the sky is highly scattered light (color). If red color scattered more then the sky would appear red instead of blue.
  • Question 3
    1 / -0
    ________ lens is used to correct the defect of vision termed as presbyopia.
    Solution
    A person may suffer from both myopia and hypermetropia. Such people often require bi-focal lenses. The upper part of $$\textbf{bifocal}$$ lens is made up of concave lens and the lower part of a small circular section is made up of convex lens. Thus, spectacles made of such a lens help to see nearby as well as distant objects clearly, a defect which is known as presbyopia. 
  • Question 4
    1 / -0
    Which phenomenon does not play a role in the formation of rainbow ?
    Solution
    $$\textbf{Absorption}$$ does not play any role in the formation of rainbow.
    • When light enters the water drop from atmosphere, refraction takes place.
    • When light after refraction enters the drop at an angle greater than critical angle, total internal reflection takes place.
    • The water droplets act like tiny prisms and disperse light into its constituent seven colours. So dispersion takes place.
  • Question 5
    1 / -0
    When sunlight enters into an atmosphere, it gets refracted. Because of this atmospheric refraction, virtual image of sun is formed during sunset and sunrise as shown in above diagram. 
    Due to this atmospheric refraction, the day __________

    Solution
    When sunlight enters into an atmosphere, it gets refracted. Due to this fact, the position of Sun appears to be slightly above the actual position during sunrise and sunset. 
    Due to this atmospheric refraction, the day becomes $$4$$ minutes longer than the actual one. 
    Correct Option is A. 
  • Question 6
    1 / -0

    Directions For Questions

    The ciliary muscles of eye control the curvature of the lens in the eye and hence can alter the effective focal length of the system. When the muscles are fully relaxed, the focal length is maximum. When the muscles are strained the curvature of lens increases (that means radius of curvature decreases) and focal length decreases. For a clear vision the image must be on retina. The image distance is therefore fixed for clear vision and it equals the distance of retina from eye-lens. It is about 2.5 cm for a grow-up person.
    A person can theoretically have clear vision of objective situated at any large distance from the eye. The smallest distance at which a person can clearly see is related to minimum possible focal  length. The ciliary muscles are most strained in this position. For an average grown-up person minimum distance of object should be around 25 cm.
    A person suffering for eye defects uses spectacles (Eye glass). The function of lens of spectacles is to form the image of the objects within the range in which person can see clearly. The image of the spectacle-lens becomes object for eye-lens and whole image is formed on retina.
    The number of spectacle-lens used for the remedy of eye defect is decided by the power of the lens required and the number of spectacle-lens is equal to the numerical value of the power of lens with sign. For example power of lens required is +3D (converging lens of focal length 100/3 cm) then number of lens will be +3.
    For all the calculations required you can use the lens formula and lens maker's formula. Assume that the eye lens is equiconvex lens. Neglect the distance between eye lens and the spectacle lens.

    ...view full instructions

    A nearsighted man can clearly object only upto a distance of 100 cm and not beyond this. The number of the spectacles lens necessary for the remedy of this defect will be
    Solution
    To correct nearsightedness, an object placed at infinity must form an image 100 cm by the corrective lens. If $$f$$ is the focal length of the lens,

     $$\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}$$

    $$\dfrac{1}{-100}-\dfrac{1}{-\infty}=\dfrac{1}{f}$$

    Therefore focal lngth of correcetive lens is $$-1m.$$
     
    Hence the power $$= -1D $$

    Number of the spectacle$$=-1$$
  • Question 7
    1 / -0
    Rising and setting sun appears to be reddish because:
    Solution
    According to Rayleigh's law of scattering, amount of scattering $$\alpha \frac {1}{\lambda^4}$$.
    Red having maximum wavelength straight to the observer.
    Most of the scattered light goes towards the sky, so the sky appears blue.
  • Question 8
    1 / -0
    A person who can see the nearer objects clearly but not distant objects is suffering from ....................
    Solution
    Myopia or near-sightedness is the condition in which the eye lens can focus images of nearby objects on the retina effectively but cannot form images of faraway objects (image is formed in the front of retina). A near-sighted person cannot see clear images of distant objects.

  • Question 9
    1 / -0
    A rainbow is formed when the air is:
    Solution
    A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky.
    These water droplets are due to moisture present in air during or after raining.
  • Question 10
    1 / -0
    How is rainbow formed?
    Solution
    A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbow is formed when sunlight on passing through water droplets during rain splits into seven colors.Splitting is due to the fact that different color light travel with different speed in water droplets.

    Hence rainbow is based on dispersion of sunlight by raindrops.
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