Q.1: Find the surface area of a cuboid which is 16.4 m long , 15.5 m broad and 8.5m high.
Q.2: A chalk box is in the form of a cube of edge 10.5cm.Find its surface area. Q.3: Find the lateral surface area of a right circular cylinder whose height is 13.5cm and radius of the base is 7cm.Find also its whole surface area. Q.4: A roller 150cm long has a diameter of 70 cm.To level a playground it takes 750 complete revolutions .Determine the cost of levelling the playground at the rate of 75 paise per sq. metre. Q.5: Find the diameter of a sphere whose surface is 346.5sq.cm. Q.6: A conical tent is 10m high and the radius of its base is 24m.Find its slant height.Also find the cost of canvas used in making the tent at Rs. 70 per sq.m. Q.7: A hemispherical bowl is made of steel 0.25cm thick .The inner radius of the bowl is 5cm .Find the outer curved surface area of the bowl. Q.8: Find the volume of a cuboid whose length is 16.4m, breadth =15.5m and height =8.5m. Q.9: A river 3m deep and 40m wide is flowing at the rate of 2km per hour .How much water will fall into the sea in a minute? Q.10 The volume of a right circular cylinder is 1100cu cm and the radius of its base is 5cm.Find its curved surface area. Q.11: A cubodal vessel is 10m long and 8 m wide.How high must be made to hold 380 cu m of a liquid. Q.12: Find the capacity in litres of a conical vessel whose diameter is 14 cm and slant height 25cm. Q.13: What are the cubical contents of a well whose diameter is 42 dm and depth 150 dm.? Q.14: The circumference of the base of a cylindrical vessel is 132 cm and its height is 25 cm .How many litres of water can it hold? [1000cu cm=1litre] Q.15: A heap of wheat in the form of cone whose diameter is 10.5m and height 3m .Find its volume. The heap is to be covered by canvas to protect it from rain. Find the area of canvas required. Q.16: The diameter of the moon is approximately one-fourth of the diameter of the earth .What fraction of the earth is the volume of the moon? Q.17: The radius of a sphere is 5cm .f the radius be increased by 20% ,find by how much %age the volume is increased. Q.18: A gowdown measures 40mx25mx10m.Find the maximum number of wooden crates each measuring 1.5m x 1.25m x 0.5m that can be stored in the gowdown. Q.19: Find the length of the longest rod that can be placed in a room 12mx9mx8m. Q.20: A 4cm cube is cut into 1cm cubes .Calculate the total surface area of small cubes. What is the ratio of surface area of small cubes to that of the large cube? Q.21: A field is 60m long and 20m wide.A tank 12m long ,10m broad and 3m deep is dug in the field .The earth taken out of it is spread evenly over the field .How much is the level of the field raised supposing the earth taken out increases by 1/8 of the volume? Q.22: A village having a population of 4000, requires 150 litres of water per head per day . It has a tank measuring 20m x 15m x 6m.For how many days will the water of this tank last ? Q.23: It costs Rs. 2200 to paint the inner curved surface of a cylindrical vessel 10m deep .If the cost of painting is at the rate of Rs. 20 per sq.m, find (i) inner curved surface area of the vessel (ii) radius of the base (iii) capacity of the vessel Q.24: The radius and height of a right circular cone are in the ratio 5:12. If its volume is 314 cu cm, find its slant height. ( take π=3.14) Q.25: A rectangular water reservoir is 7.2m by 2.5m at the base . Water flows into it through a pipe whose cross section is 5cm x 3cm at the rate of 10m per second .Find the height to which the water will rise in the reservoirs in 40 minutes. 1. An object is placed between two plane mirrors inclined at an angle of 45° to each other. How many images do you expect to see?
2. A convex mirror is held in water. What should be the change in its focal length? 3. If the light from the Sun subtend an angle Q at the pole of a concave mirror of focal length f, where will it converge? Also find the diameter of the image. Draw the necessary ray diagram. 4. When does Snell’s law of refraction fail? 5. How does the frequency of a beam of ultraviolet light changes when it goes from air to glass? 6. State two conditions under which a ray of light suffering refraction from medium 1 to medium 2 does not undergo any change in direction 7. Name the factor on which lateral shift produced by glass slab depends? 8. A glass lens is immersed in water. How is the power of the lens affected? 9. Why is the power of a lens is measured as reciprocal of focal length? Give reason. 10. A convex lens is made of a material of refractive index m1 when placed in a medium of refractive index m2, behaves as a diverging lens. How are m1 and m2 related? 11. An object is held at a distance of 60 cm from a convex mirror of focal length 20 cm. At what distance from the mirror, should a plane mirror be held so that images in the two mirrors coincide?(ans. 22.5 cm) 12. How do you find the rough focal length of a convex lens? Is the same method applicable to a concave lens? 13. Which factors determine the focal length of a lens? 14. The formula for linear magnification of a spherical mirror is m=h’/h = -v/u. What determines the sign of m? What is the significance of this sign? 15. A convex lens made of material of refractive index n2 is kept in a medium of refractive index n1. A parallel beam of light is incident on the lens. Compare the path of rays of light emerging from the convex lens if (i)n1<n2 (ii)n1=n2 (iii) n1>n2 16. A concave lens of focal length 25 cm and a convex lens of focal length 20 cm are placed in contact with each other. What is the power of this combination? Also, calculate focal length of this combination. (ans. 1m) 17. A convergent lens of power 8D is combined with a divergent lens of power -10 D. Calculate focal length of the combination. (ans.-0.5 m) 18. A concave lens has a focal length of 15 cm. At what distance should an object from the lens be placed so that it forms an image at 10 cm from the lens? Also find the magnification of the lens. 19. Under what condition in an arrangement of two plane mirrors, incident ray and reflected ray will always be parallel to each other, whatever be the angle of incidence? Show the same with the help of diagram. 20. How much time will light take to cross 2 mm thick glass pane if refractive index of glass is 3/2? (ans. 10-11s) 21. Light travel from rarer medium 1 to a denser medium 2. The angle of incidence and refraction are respectively 45° and 30°. Calculate the refractive index of second medium with respect to the first medium. 22. A pond of depth 20 cm is filled with water of refractive index 4/3. Calculate apparent depth of the tank when viewed normally. 23. Light of wavelength 500nm in air enters a glass plate of refractive index 1.5. Find (a)speed. (b)frequency, and (c)wavelength of light in glass. Assume that the frequency of light remains the same in both media. 24. A myopic person prefers to remove his spectacles while reading a book. Give reason. 25.A hypermetropic person prefers to remove his spectacles while driving a vehicle. Give reason Solution: Light Refraction and Refraction solved questions-5 Download File Class 10th (SA-II), Session:2012-13 Chemistry Assignment- IV
Chapter :(carbon and its compounds) 1. An organic compound X with a molecular formula C2H6O undergoes oxidation with in presence of alkaline KMnO4 to form a compound Y. X on heating in presence of Conc. H2SO4 at 443K gives Z. Which on reaction with H2Oin presence of H2SO4 gives back `X` `Z` reacts with Br2 (aq) and decolorizes it. Identify X, Y, & Z and write the reactions involved. 2. An organic compound ‘A’ is widely used as a preservative in pickles and has a molecular formula C2H2O2. This compound reacts with ethanol to form a sweet smelling compound ‘B’. (i) Identify the compound ‘A’ (ii) Write the chemical equation for its reaction with ethanol to form compound ‘B’. (iii) How can we get compound ‘A’ back from ‘B’? (iv) Name the process and write corresponding chemical equation. (v) Which gas is produced when compound ‘A’ reacts with washing soda? Write the chemical equation. 3. Hydrocarbon `X` and `Y` having molecular formulae C3H8 and C3H6 respectively. Both are burnt in different spatula on the Bunsen flame. Indicate the color of the flame produced by `X` and `Y`. Identify `X` and `Y`. Write the structural formulae. 4. A compound `X` has molecular formula C4H10. It undergoes substitution reaction readily than addition reaction. It burns with blue flame and is present in LPG. Identify `X` and give the balanced equation for its combustion and substitution reaction with Cl2 in presence of sunlight. 5. `A` compound works well with hard water. It is used for making shampoos & products for cleaning clothes. A is not 100% biodegradable and causes water pollution. `B` does not work well with hard water. It is 100% biodegradable and does not create water pollution. Identify A & B. 6. An organic compound P with molecular formula C2H6Ois an active ingredient of all alcoholic drinks. It is also used in medicines such as tincture iodine, cough syrups. Identify `P`. Drop a small piece of sodium into the test tube containing `P`.A new compound `Q` is formed with the evaluation of colorless and odorless gas Name the gas evolved and compound `Q` write the chemical reaction. 7. A cyclic compound `X` has molecular formula C6H6. It is unsaturated and burns with sooty flame. Identify `X` and write its structural formula. Will it decolorize bromine water or not and why? 8. An organic compounds `A` is a constituent of antifreeze and has the molecular formula C2H6O upon reaction with alkaline KMnO4, the compound `A` is oxidized to another `B` with formula C2H6O2. Identify the compound A` and `B`. Write the chemical equation for the reaction which leads to the formulation of `B` 9. Two compounds `X` and `Y` have the same formula C2H4O2. One of them reacts with sodium metal to liberate H2 and CO2 with NaHCO3. Second one does not reacts with Na metal and NaHCO3 but undergo hydrolysis with NaOH to form salt of carboxylic acid and compound `Z` which is called wood spirit. Identify `X`, `Y`, and `Z` and write chemical equation for the reaction involved. 10. A compound `X` with molecular formula C2H4 burns with a sooty flame. It decolourise bromine water. Identify `X`. Will it dissolve in water or not? Will it conduct electricity in aq. Solution? Will it have high melting point or low melting point? 11. Write the formula for ‘ethanoic acid’ and name the functional group present in it. 12. Allotropy is a property shown by which class: - Substances, elements, compounds, mixture. 13. What is the use of oxyacetylene flame? 14. Name the gas which is formed by decomposition of plants and animal matter in marshy areas? 15. Mention the name of the byproduct of soap industry. 16. Write the molecular formula and structures of benzene. 17. Match the following:- 1. Ethane - Used in anti freeze solution. 2. Ethanol - fruity smell. 3. Ester - fossil fuel. 18. Write two uses of fullerenes. 19. Complete and balance following equation:- a) CH2=CH2 + H2 heat, Ni b) CH4+O2 20. Two alkanes A and B have 4 and 6 carbon atoms respectively in their molecule. In which physical state will they occur at room temp? 21. Give a test that can be used to differentiate chemically between butter and cooking oil. 22. How will you distinguish between ethanol and ethanoic acid by a suitable chemical test? Write chemical reactions involved. 23. Complete the following reactions:- 1) CH3COOH + NaHCO3 conc.H2SO4 2) HCOOH + CH3OH 3) CH3COOC2H5 + H2O 24. Name the compound CH3COOC2H5.Name the acid and alcohol from which it is made, write equation. http://www.davblb.ac.in/assignments.asp What is environment?
The sum total of all surroundings of a living organism, including natural forces and other living things, which provide conditions for development and growth as well as of danger and damage is called environment. What happens when we add our waste to the environment or throw ? When we add our waste to the environment some of them are broken down by the biological processes but rest persists for a long time. What are the different types of waste materials? Waste that are broken down by the biological processes are said to be biodegradable. These wastes are decomposed through the actions of fungi, bacteria and other living organisms and enrich soil fertility. Examples: Food refuse, tree leaves urine and faecal matter, ewage agricultural residue, paper, wood, cloth, cow-dung, etc Waste that are not broken down by the biological processes are said to be non biodegradable. These substances are inert and simply persist in the environment for a long time or may harm the various members of the ecosystem. Example ; these includes DDT, insecticides, pesticides, mercury, lead, arsenic, aluminimum, plastics, polythene bags, glass, radioactive wastes. What happens after we throw waste away them away? Fungi, bacteria and other living organisms in the presence of temperature and sunlight act on waste and try to break down. Why are some substances biodegradable and some non-biodegradable? Some substances are biodegradable and some are non bio-degradable. This is because of the specific action of the enzymes produced by bacteria or decomposers. The enzymes can break down natural substances into non poisonous simpler substances but cannot act on man-made substances like plastics What are the harmful effects of biodegradable substance? 1. This waste destroyed the natural beauty and surroundings become dirty. 2. Decomposition of these wastes results in the production of foul smell, which spreads to surroundings areas. 3. These wastes may also block the drains creating pools of waste which becomes the breeding sites of mosquitoes. The letter is carriers of diseases like malaria and dengue. What are the harmful effects of non- biodegradable substance? 1. These wastes are very harmful. They enter the food chains and their concentration goes on increasing from one trophic level to the next. This leads to biological magnification and result in harmful effects in human beings and other animals. 2. Dumping these wastes affects the soil fertility and subsequently reduces the crop yield. 3. Non-biodegradable chock out the sewage system and pollute the soil. 4. Some of the non-biodegradable substances may toxic for the humans and produce various diseases. Name some of the biodegradable plastics. Polyhydroxyalkanoates (PHAs) like the poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhexanoate (PHH) . What are the differences between biodegradable and non-biodegradable wastes. Biodegradable Wastes 1. The wastes are broken down naturally by microbial action 2. Biodegradation forms harmless and nonpoisonous products. 3. They release raw materials back to nature. 4. They pollute the environment only when they are produced in quantity beyond the capacity of environment to degrade them. 5. Recycling is possible either naturally or through human efforts. Non-biodegradable 1. The wastes are not broken down by the microbes. 2. No such action is possible. 3. They do not release raw materials. 4. Non-biodegradable wastes pollute the environment even in small quantity. 5. Recycling is possible only through human efforts. What is echo system? Ecosystem is a structural and functional unit of the biosphere consisting of a community of living beings and the physical environment. For example: forests, ponds and lakes are natural ecosystems while gardens and crop-fields and aquarium are human made (Artificial) ecosystems. What are the different types of echo system? Natural ecosystems are grass land, a forest, a sea, a river, a desert, a mountain, a pond, a lake etc. The desert, grass land and mountain represent the terrestrial ecosystem (land based ecosystem). The ponds, rivers, lakes and sea represent the aquatic ecosystem (water- based ecosystem). Man – made or artificial ecosystems are garden, crop fields, park aquarium, etc. Why does aquarium have to be cleaned once in a while? To remove fish wastes from the water because there are no bacteria and fungi to break-down the dead remains and waste products of organisms. --------------==================================--------------------- 10th Science - Our Environment: Summative assignments View/Read 10th Chapter: Our Environment Questions Paper for FA-III View/Read 10th Science: Chapter: Our Environment HOTS Questions View/Read 10th Chapter: Our Environment: Gist of Lesson View/Read 10th Our Environment CBSE SOLVED GUESS PAPER Download |
Blog SeaRCH Link
All
Join Us For Update |