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NCERT SOLUTION CLASS 9 SCIENCE EXERCISE

NCERT SOLUTION OF CHAPTER 1 OF CBSE BOARD CLASS 9 ( MATTER IN OUR SURROUNDINGS)  EXERCISE  PAGE NO 12 QUESTION NO 1      Convert the following temperatures to the celsius scale. (a) 293 K           (b)   470 K ANSWER    (a)  293 K = 293-273 = 20 degree centigrade   (b) 470 K = 470-273 = 197 degree centigrade   QUESTION NO 2    Convert the following temperatures to the kelvin scale. (a) 25 degree centigrade      (b) 373 degree centigrade  ANSWER     (a) 25 degree centigrade =    25 + 273= 298 K (b) 373 degree centigrade = 373+273 = 646 K QUESTION NO 3       Give  reason for following observation observations. (a) Naphthalene balls disappear with time without leaving any solid. (b) We can get the smell of perfume sitting several metres away. ANSWER  (a) Naphthalene ...
CLASS - 10 SCIENCE IMPORTANT QUESTIONS PART - 2  QUESTION NO. 11  Write the name of lens which is called diverging lens. Why it is called diverging. ANSWER NO. 11 Concave lens diverging light rays. Such lenses are called diverging lenses. QUESTION NO. 12 A paper is burnt through a lens. Write the name of lens. ANSWER NO. 12 Convex lens. QUESTION NO. 13 The human eye can focus on object at different distances by adjusting the focal length of the eye lens. This is due to  (a) Presbyopia (b) Accommodation (c) Near - sightedness    (d) Far - sightedness ANSWER NO. 13 (b) Accommodation QUESTION NO. 14 If the earth had no atmosphere, the sky will look - (a) Blue (b) Red  (c) Yellow  (d) Dark blue  ANSWER NO. 14 (d) Dark blue QUESTION NO. 15 To the passengers flying in very high altitude the sky will look - (a)  Red  (b)  Yellow  (c)  Pink (d)  Dark Blue ANSWER NO. 15 (d...

CLASS - 10 SCIENCE IMPORTANT QUESTIONS PART -

CLASS - 10 SCIENCE IMPORTANT QUESTIONS PART - 1 QUESTION NO .1 Write the characteristic of image formed by plane mirror. ANSWER .1 Image formed by a plane mirror is always virtual and erect. The size of image is equal to the that of object. The image is formed as far behind the mirror as the object is in front of it . QUESTION NO. 2 Write the name of mirror which is used as rear view in vehicle . ANSWER NO. 2 Convex mirrors are commonly used as rear view mirrors in vehicle . QUESTION NO. 3 Define magnification of image . ANSWER NO. 3 Magnification produced by spherical image gives the relative extent to which the image of an object is magnified with respect to the object size . QUESTION NO. 4 What is meant by power of accomodation of the eye . ANSWER NO. 4 The ability of the eye lens to adjust its focal length is called accomodation . QUESTION NO. 5 What is aperture . ANSWER NO. 5 The diameter of the reflecting surface of spherical mirror is cal...

WHAT IS VITAMIN C

WHAT IS VITAMIN C         Vitamin C is a ascorbic acid. It is a water soluble vitamin which found in many foods,specially in fruits and vegetables. It is a potent antioxidant and having positive effect on skin and immune function of the body. It is also vital for collagen synthesis,connective tissue,bones,teeth and small blood vessels.       The human body cannot produce or store vitamin C. Hence it is necessary to consume it regularly in adequate amount. DEFICIENCY OF VITAMIN C  The deficiency of vitamin C may cause bleeding gums,frequent bruising and infections,poor wound healing,anaemia and scurvy. FUNCTION OF VITAMIN C 1. It protect cells from free radical damage. 2. It is required to make a collagen. 3. It improves iron absorption. SOURCE OF VITAMIN C Citrus fruit such as orange,kiwi,lemon,guava and grapefruit are rich natural source of vitamin C.

WHAT IS VITAMIN B

WHAT IS VITAMIN B     There are 13 vitamins that our body required,eight of which make up the B-group it is also called vitamin B- complex. It is important for function of cells properly in the body. It also helps to create new blood cells,in maintaining healthy skin cells,brain cells and other body tissue.     It is a group of eight types which are as follows 1.      thiamin (vitamin B-1) 2.      riboflavin (vitamin B-2) 3.     niacin (vitamin B-3 ) 4.    pantothenic acid (vitamin -B5) 5.    vitamin B-6 6.    biotin (vitamin B-7) 7.    folate (vitamin B-9) 8.   vitamin B-12      Together they are called vitamin B complex. They are water soluble. They are easily destroyed,particularly by alcohol and cooking. Food processing can also reduce the amount of B-group vitamins in food. The body has a limited capacity to store most of the B-group vitam...

WHAT IS VITAMIN A

WHAT IS VITAMIN A        Vitamin A is a fat soluble which plays a important role in the body. It is present in the food and it can also be taken in the form of supplements.      In food two type of vitamin A found which are as follows 1. Preformed vitamin 2. Provitamin A Preformed vitamin A are retinol and  retinyl ester which are found in the liver,fish and the dairy product where as provitamin A carotenoids are abundents in plant food like fruits,vegetables and oils.   After the intake of two form of vitamin a our body convert it in retinal and retonic acid which are the active form of the vitamin. Since vitamin A is the fat soluble vitamin hence it is stored in the body tissue. It is also stored in the liver in the form of retinyl esters.   FUNCTION OF VITAMIN A      The main role of the vitamin A is the vision and eye health. Apart from it is also important in supporting cell growth,immune function,fetal ...

WHAT IS HOMOGENEOUS MIXTURE

WHAT IS HOMOGENEOUS MIXTURE     In homogeneous mixture components mixed uniformly distributed throughout the mixture. The homogeneous mixture has the following characteristics -- 1. Particles are distributed uniformly. 2. It has uniform composition. 3. Homogeneous mixtures are also called solution. 4. In homogeneous mixture the mixed components will not separated out over time.  Examples of homogenous mixtures are air,solution of sugar,alloys etc