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Long ans less 14, Ans 3 - All the different parts of your eyes work together to help you see., First, light passes through the cornea.The cornea is shaped like a dome and bends light to help, the eye focus., Some of this light enters the eye through an opening called the pupil . The iris controls how, much light the pupil lets in., Next, light passes through the lens. The lens works together with the cornea to focus light, correctly on the retina., When light hits the retina, special cells called photoreceptors turn the light into electrical, signals., These electrical signals travel from the retina through the optic nerve to the brain. Then the, brain turns the signals into the images, Ans 2- The Two Laws of Reflection., 1.When a ray of light falls on a reflecting surface, it is reflected in such a way that the angle of, incidence is equal to the angle of reflection i.e.,, 2. The incident ray, the normal and the reflected ray, all lie in the same plane, , Lesson 14 exercise
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Tick the correct, 1- Iris., , 2.Reflection of light, , 3.Transparent, , 4.Two, , 5. Incident Ray, True or false, 1- F. 2- T. 3 -F 4 -F 5 -T 6- F, Fill in the blanks, 1- Reflection, 5, , 2.Incident Ray., , Braille., , 1820, , 3.Point of incident, , 4……., , 6.Light, , Define the following. ( Lesson 14, Reflection of light :- When a ray of light falls on any object (polished, smooth, shiny, , object), light from that object bounces back those rays of light to our eyes and this is, known as “Reflection” or “Reflection of Light”., Dispersion :- Dispersion of light is the splitting of white light into its, constituent colors due to the refractive index of the surface and the, wavelength of the light., Blind spot :- It is reason below the yellow spot where no light sensitive nerves, ending are present it is an area of no vision., Blindness:- A person is to be blind or visually impaired when he or she is, unable to see is called blindness., Myopic eye :- In this eye defect the person can see nearer object clearly but cannot see fat off, object ., Defirence between lesson 14, 1. Myopia and hypermetropia
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Myopia- in this in this defect the person can see near object clear but cannot see, the path of object. This defect is due to the thickness of the eye lens., Hypermetropia- in this eye effect the person can see part of objects clearly but, cannot see the near objects this defect due to the thinness of the eye lenses, 2. Temporary blindness and permanent blindness, Temporary blindness – when of cornea becomes opaque or the crystalline, becomes opaque in both case person is operates upon the site is restored this type, of blindness is called temporary blindness., permanent blindness:- in the case the cornea make an image but it is not, transferred to the , this type of blindness is called permanent blindness., 3. The image formed by the old utensil is little bit blur. This is because the surface, of the utensils is rough . the image which is formed by a new utensil is correct., This is because the surface of the utensil is smooth., , 4. Regular and Diffused reflection, Regular reflection – the surface of a mirror is very smooth therefore if a beam of, light falls on it the entire beam is reflected in only one direction this is called regular reflection., Diffused reflection – twhen the ray or a beam of light falls on the object with an, uneven surface they get reflected in different direction this is called is diffused reflection., 5. 3 image formed by the two plane mirror arranged at the angle of 90 degree and, the 5 image formed by two plane mirror arranged at an angle of 60 degree, , Short answer lesson 14, Ans 1- reflection of light throwing back of light by the object., Ans 2- regular reflection- if a beam of light fall on smooth surface, it the entire, beam is reflected in only one direction this is called regular reflection, Ans4- virtual image - that image cannot be caught on the screen because there is, no actual meeting of the light .
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Ans 5-multiple reflection- Multiple reflection of light is the reflection of, , light back and forth through reflecting surfaces several times., When the reflection of a reflected light ray on another object is, mirrored again, it is called multiple reflections., Ans 6- VIBGYOR- the seven colour are same as those seen in a, rainbow violet Indigo blue green yellow orange and red it is also, called VIBGYOR., Ans 7- in this method text is written on the thick paper using, special symbol representing the letter of the alphabet groups of, dot are employed to written letter., .
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Long answer lesson 13, , Ans long 5 -When clouds of opposite charges come close to each other, heavy exchange of, electrons take place causing 8-5 production of large amount of energy in the form of light, heat, and sound. The light and heat energy is seen as the lightning and sound energy is heard as a great, thunder, , Ans long 2. The charging of the bodies is due to the transfer of electrons. When an object looses, the electron, there is excess of the positive protons and, thus, the atom becomes positively
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charged. When other atom gains the lost electrons, the number of electrons become more than, the protons and it be comes negatively charged
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Class 8 lesson 13 Short answer, , 1. Comb attract bits of paper towards it. this means both comb and paper, had developed some force which attract or repel object when these, object where they develop charge., 2. Electric energy e produce bye exchange of electron is called charge, 3. charge are two type 1. Positively charged: electrons are removed making the, object electron deficient., Negatively charged: electrons are added giving the object an excess of, electrons., •, , 4. many time we see a flash of cloud in the sky which is followed by a loud, sound called thunder., The bright flash of light which we see in the cloud is called lightening., 5. Tall building can we e save from lightening by the the use of lightning, conductor on the roof which is connect to the earth when lightning is, fall on the roof these lightening conductor attract and transfer in the, earth., 6. Advantage of the lightning – a) lightning is is also very important in, forming ozone layer. B) lightening form of dilute nitric acid which, dropdown in the form of rain. It form nitroginous compounds.
