Explain parts of human eye and its functions....

Difference between internal reflection and total internal reflection

Draw a labeled diagram of human eye. Write the functions of Cornea, Iris, Pupil, eye lens and retina.

How to solve numericals related to myopia and hypermetropia? Plz explain.

When we enter from bright sunlight to a dark room, we cannot see initially, why?

What is the most sensitive part of the retina

A ray of light undergoes total internal reflection while moving from a denser to a rarer medium . Derive the relation connecting critical angle and refractive indices of the two media .

Why the Danger Signals are red in Colour ?

what is scattering of light ?

Explain the construction and working of human eye? (4 MARKS)

what is power of accommodation??

what is the difference between deviation and dispersion

 Give examples of daily life where dispersion of light is seen?

what is incident ray and emergent ray ?

Why mirror does not have power?

explain delayed sunset and advanced sunrise.... why does it happen( give proper reason).....

plz help.....

why does sun appear red during sunrise and sunset

what is the function of rod and cone cells in human eye?

What is the power of normal eye lens?

what is the relation between angle of incidence ,angle of deviation ,angle of prism and angle of emergence?

The ray diagram of formation of rainbow by a raindrop is not correct. After total internal reflection when the ray is shown to be coming out of the water droplet then after refraction the ray is shown to be bending towards the normal rather than away from the normal which is against the laws of refration. Please clarify.

why is a normal eye not able to see clearly the objects placed closer than 25 cm

arrange the rainbow colours in ascending order according to its wavelength. Also tellthe advantagelonger wavelength and shorter wavelength.

draw a ray diagram to show the refraction of light through a glass prism .On this diagram plz mark :

a)incident ray

b)emergent ray,

c)angle of deviation

What is stereopsis?

why does a glass slab not disperse white light ?

what is the difference between color blindness and night blindness? According to its pigments

define angle of prism?

1.  The near point of a hypermetropic person is 75 cm from the eye. What is d power of  d lens required to enable him to read clearly a book held at 25 cm from the eye?

2.  If the person in the previous problem uses spectacles of power +1.0 D wat is d nearest dist. of distinct vision for him?

What is the power of the given lens?

Solution:

Only real images can be obtained on a screen. Also, real images can be formed by convex lenses only. Hence, the power of the lens will be positive. The power of a lens is defined by the formula,

The lens formula can be used to calculate the focal length,f. It is given as,

Since real images are formed behind a convex lens, the image distance will be positive, while the object distance will be negative.

Object distance,u= −40 cm

Image distance,v= 50 cm

Focal length =f

Hence, the power of the given lens is 4.5 D. The positive sign indicates that the lens is convex.

The correct answer is C.

MY DOUBT: HOW DID YOU ARRIVE AT THE CONCLUSION THAT OBJECT DISTANCE IS -40 CM ?

The sun is visible to us about 2 minutes before actual sunrise and about the actual sunset.give reasons.

Explain the formation of rainbow briefly?

is the angle of incidence equal to the angle of emergence in a glass prism(triangular) and in a glass prism?

how are angle of prism and angle of deviation related to each other?

 list three problems which arise due to construction of big dams. suggest a solution for these problems.

State two properties of the image formed by the eye lens on the retina.

explain structure of human eye?

An old person is unable to see clearly near by object as well as distant object.

a] What defect of vision is he suffering from?

b] What knid of lens will be required to see clearly the near by as well as distant object? Give reason.

These are the question's which i am doubts ... please type the answer for these questions so that it would be helpful for me....please take it as serious matter and reply for these questions ... PHYSICS:- 1) What do you mean by lateral displacement? 2) What is the cause of dispersion of light? 3) What makes bees respond to ultraviolet rays? 4) Name the liquids that keeps our eye soft? 5) Show that the mirror formula holds good for a plane mirror? 6) Why chickens stroll only during noon while they go back early in the evening? 7) What is mean by illumination ? 8) Define the scattering of light? BIOLOGY:- 1) The PH range most conductive for life of freshwater plants and animals is (i) 6.5 - 7.5 (ii) 2.0 - 3.5 (iii) 3.5 - 5.0 (iv) 9.0 - 10.5 2) What would be the advantage of exploiting resources with long term aim? 3) What is the objective of Ganga action plane? 4) Red data book provides the list of (a) Protected animals (b) Rear animals for milk (c) entrap animal (d) Both (a) & (b) 5) Write any two ways of energy flow through on ecosystem? 6) Why is pond self sustaining unit while an aquarium may not be? Justify the answer. 7) What will be the impact on ecosystem if bacteria and fungi are removed from the environment? 8) Name any two environment friendly practices? 9) What is being done to avoid ozone depletion? 10) Describe any five modes of disposal of wastes? 11) Ecology is the study of interaction of ______________ with other and their surroundings. 12) De composers are also called as __________________. 13) Water , air, light,and temp. are the examples of _____________ components. 14) Give an example of bisexual flower what is its female reproductive part known as. 15) Pollination may occur without fertilization but fertilization will not take place pollination. Give reason? 16) Define :- (i) Fragmentation (ii) Vegetative Propagation. 17) Advantages and Disadvantages of Vegetative Propagation ? 18) Explain Tissue Culture? 19) Write the differences between Binary fission and Multiple Fission in a tabular form as observed in cells of organism? 20) List any four characteristics of Good fuel? 21) List the sexual transmitted diseases (i) Bacterial infection. 22) Explain the term (i) Speciation (ii) Natural selection. 23) Explain how equal genetic contribution of male and female parents is ensured in the progeny?

explain why the sky appears dark on the surface of the moon??

solve for x

[4x-3/2x+1] - 10[2x+1/4x-3] = 3

why do we observe changes in colour of sun at sunrise,sunset and noon?

why only 7 coloured spectrum emerges from a prism??

what 's function of aqueous humour & Vitreous humour

 a short sighted person can see most clearly at a distance of 15 cm,acquires spectacles enabling him to see most clearly objects at a distance of 60 cm. calculate the total length of the lens and power of the lens

Why do stars twinkle?

Explain why the planets do not twinkle?

Why does the Sun appear reddish early in the morning?

the ratio of real depth to apparent depth is called what and why?

 list the three phenomenon of light responsible for the formation of rainbow in the sky

Why does sun appear in oval shape during sunset and sunrise? explain with the help of ray diagram.

What is meant by point source and external source?

Why does the Sun appear reddish early in the morning?

How does tyndall effect help us to see a movie in a theatre?

 Why does stars twinkle but planets do not?

"We are able to see through a transparent medium as light is transmitted through it." What does this line mean?

what is optical density?How it decreases as we move away from earth's surface?

Draw a neat and label diagram of human eye and explain functions of each part of human eye.

How does the focal length of the eye lens change when we shift looking from a nearby object to a distant object ?

Give reasons for the following:-

a) Colour of clear sky is blue.

b)Sun can be seen about two minutes before actual sunrise.

c)Traffic light signals are of red colour.

d)Stars appears to twinkle.

e)Planets do not twinkle.

what is Persistence of vision?

A student has difficulty in reading the blackboard while sitting in last row. What could be defect of vision? Draw ray diagrams to illustrate this defect and its correction.

A lens of focal length 5 cm is being used by a student in the laboratory as a magnifying glass. His least distance of distinct vision is 25 cm. What magnification is the student getting?

The near point of a person suffering from hypermetropia is 75cm. Calculate the power of lens required to enable him to read the newspaper which is kept at 25cm from the eye.

Why do we have two eyes for vision and not just one ??

 What is choroid and its function ?

 what is the difference between myopia and presbyopia?

 how does rainbow form?

Make a diagram to show how hypermetropia is corrected. The near point of a hypermetropic eye is 1 m. What is the power of the lens required to correct this defect? Assume that the near point of the normal eye is 25 cm.

what do you mean by far and near point in human eye

 draw a ray diagram of myopic eye and its rectification.

The surface of sunglasses is curved, yet their power is zero. Why?

1. Why do stars twinkle and hence why do planets do not twinkle?

2. Give reason for the following: (a) Blue colour of the sky (b) Red colour of danger signals.

3. Give reason for the following (a) White colour of clouds (b) Sun appears red at the time of sun set and sun rise.

4. Explain Tyndal Effect.

5. What is rainbow? Give the conditions for observing it. State the principle involved in the formation of rainbow.

WHICH LENS ARE PRESCRIBED TO SOLVE PRESBYOPIA

short note on :- myopia and hypermetropia ?