Human eye and the colorful world - COMPLETE PLAYLIST -

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Structure of Human Eye

Working of Human Eye

Power of accommodation of eye

Ability of human eye to change its focal length

Q.1 : Which is responsible for changing the focal length of eye lens

Ciliary muscles

Pupil

Cornea

Iris

A.

C.

B.

D.

Q.1 : Which is responsible for changing the focal length of eye lens

Ciliary muscles

Pupil

Cornea

Iris

A.

C.

B.

D.

DEFECTS IN VISION

Nearsightedness (Myopia)Correction: Concave lens Farsightedness (Hypermetropia)

Correction : Convex lens

DEFECTS IN VISION

Nearsightedness (Myopia)Correction: Concave lens

DEFECTS IN VISION

Farsightedness (Hypermetropia)Correction : Convex lens

Q.2 : A person cannot see objects nearer than 75 cm from his eyes while a person with normal vision can see objects upto 25 cm from his eyes. Find the nature and the power of the correcting lens used for the defective vision.

Hypermetropia, +2.67 D , Convex lens

Hypermetropia,-1.66D , Convex lens

Myopia, -2.67 D , Concave lens

Hypermetropia, 1.66 D , Concave lens

A.

C.

B.

D.

SOLUTION

Q.2 : A person cannot see objects nearer than 75 cm from his eyes while a person with normal vision can see objects upto 25 cm from his eyes. Find the nature and the power of the correcting lens used for the defective vision.

Hypermetropia, +2.67 D , Convex lens

Hypermetropia,-1.66D , Convex lens

Myopia, -2.67 D , Concave lens

Hypermetropia, 1.66 D , Concave lens

A.

C.

B.

D.

DEFECTS IN VISION

Presbyopia (Old age Hypermetropia)Correction : Convex lens Cause: weakening of ciliary muscles due to old age

DEFECTS IN VISION

Presbyopia (Old age Hypermetropia) + MyopiaCorrection : Both Convex lens & Concave lensCause: weakening of ciliary muscles due to old age

Q.3 : A person can see objects lying between 0.5 m and 2m . He is suffering from:

Astigmatism

Hypermetropia

Myopia

Presbyopia

A.

C.

B.

D.

Q.3 : A person can see objects lying between 0.5 m and 2m . He is suffering from:

Astigmatism

Hypermetropia

Myopia

Presbyopia

A.

C.

B.

D.

Refraction through a prism

● Dispersion : Process of splitting of white light into its component colours.

Refraction through a prism

● Angle of deviation(∠D): Angle between the incident and the emergent ray

Refraction through a prism

Q.4 : When light enters a prism, it gets split into its constituent colours. This is due to

Different refractive index for different wavelength of each colour

Prism material have high density

Each colour has same velocity in the prism

Scattering of light

A.

C.

B.

D.

Q.4 : When light enters a prism, it gets split into its constituent colours. This is due to

Different refractive index for different wavelength of each colour

Prism material have high density

Each colour has same velocity in the prism

Scattering of light

A.

C.

B.

D.

Q.5 : Consider light passing through prism made of different materials. The materials have refractive index of 1.1, 1.3, 1.5, 1.7 respectively. Light deviates the least in prism of refractive index

1.1

1.5

1.3

1.7

A.

C.

B.

D.

Q.5 : Consider light passing through prism made of different materials. The materials have refractive index of 1.1, 1.3, 1.5, 1.7 respectively. Light deviates the least in prism of refractive index

1.1

1.5

1.3

1.7

A.

C.

B.

D.

Human eye and the colorful world - COMPLETE PLAYLIST -

ATMOSPHERIC REFRACTION

● Deviation of light as is passes through the atmosphere due to the variation in refractive index of air

● Celestial bodies appear higher due to atmospheric refraction.

ATMOSPHERIC REFRACTION

Twinkling of Stars

● Varying Refractive index causes the twinkling of stars.● Since planets are considered as the collection of points, their

twinkling effect averages out

Real and apparent sunrise and sunset

● Atmospheric refraction makes the sun appear higher than it is

Horizon line

Q.6 : The air layer of atmosphere whose temperature is less than the hot layer behaves as optically

Denser medium

Inactive medium

Rarer medium

Either denser or rarer medium

A.

C.

B.

D.

Q.6 : The air layer of atmosphere whose temperature is less than the hot layer behaves as optically

Denser medium

Inactive medium

Rarer medium

Either denser or rarer medium

A.

C.

B.

D.

Scattering of light: Spreading of light rays

Scattering decreases the intensity

Scattering of light in the atmosphere gives:Orange colour to the sun during sunset and sunrise

Scattering of light in the atmosphere gives:Blue colour to the sky

Q.7 : Danger signs are ________ in colour as it scatters the ________

Red, most

Violet, most

Red, least

Violet, least

A.

C.

B.

D.

Q.7 : Danger signs are ________ in colour as it scatters the ________

Red, most

Violet, most

Red, least

Violet, least

A.

C.

B.

D.

Q.8 : Which one of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset.

Dispersion of light

Total internal reflection of light

Scattering of light

Reflection of light from the earth

A.

C.

B.

D.

Q.8 : Which one of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset.

Dispersion of light

Total internal reflection of light

Scattering of light

Reflection of light from the earth

A.

C.

B.

D.

Q.7 : Danger signs are ________ in colour as it scatters the ________

Red, most

Violet, most

Red, least

Violet, least

A.

C.

B.

D.

Human eye and the colorful world - COMPLETE PLAYLIST -

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