Q. 1) (a) A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the position, nature and size of the image formed. (b) Draw a labelled ray diagram showing object distance, image distance and focal length in the above case. Q.2) (a) Draw a diagram of human female reproductive system and label the parts : (i) which produce an egg. (ii) where fertilization takes place. (b) List two bacterial diseases which are transmitted sexually. (c) What are contraceptive devices ? Give two reasons for adopting contraceptive devices in humans. Q. 3) (a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it. (b) Why do stars twinkle ? Explain. (c) Write the function of each of the following parts of human eye : (i) Cornea (ii) Iris (iii) Crystalline lens (iv) Ciliary muscles (d) Why does the sun appear reddish early in the morning ? Will this phenomenon be observed by an astronaut on the Moon ? Give reason to justify your answer. Q. 4) (a) Define excretion. (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions : (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out. Q. 5) Distinguish between esterification and saponification reactions with the help of the chemical equations for each. State one use of each (i) esters, and (ii) saponification process. Q. 6) State the cause of dispersion of white light by a glass prism. How did Newton, using two identical glass prisms, show that white light is made of seven colours ? Draw a ray diagram to show the path of a narrow beam of white light, through a combination of two identical prisms arranged together in inverted position with respect to each other, when it is allowed to fall obliquely on one of the faces of the first prism of the combination. Q. 7) a ) 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid. b) The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses. Q. 8) Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity. Q. 9) a) Mention any two components of blood. (b) Trace the movement of oxygenated blood in the body. (c) Write the function of valves present in between atria and ventricles. (d) Write one structural difference between the composition of artery and veins. Q. 10) i) You might have noted that when copper powder is heated in a china dish, the reddish brown surface of copper powder becomes coated with a black substance. (a) Why has this black substance formed ? (b) What is this black substance ? (c) Write the chemical equation of the reaction that takes place. (d) How can the black coating on the surface be turned reddish brown ? Ii) 2 g of ferrous sulphate crystals are heated in a dry boiling tube. (a) List any two observations. (b) Name the type of chemical reaction taking place. (c) Write balanced chemical equation for the reaction and name the products formed. Iii) In an industrial process used for the manufacture of sodium hydroxide, a gas ‘A’ is formed as a by-product. The gas ‘A’ reacts with lime water to give a compound ‘B’ which is used as a bleaching agent in the chemical industry. Identify ‘A’ and ‘B’. Also give the chemical equations of the reactions involved.
Answers
Explanation:
(A) Light - Reflection and Refraction. A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. ... Thus, a real and inverted image which is 10 cm tall, is formed at a distance of 60 cm on the right side of the lens.
Answered
Q. 1) (a) A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the position, nature and size of the image formed. (b) Draw a labelled ray diagram showing object distance, image distance and focal length in the above case. Q.2) (a) Draw a diagram of human female reproductive system and label the parts : (i) which produce an egg. (ii) where fertilization takes place. (b) List two bacterial diseases which are transmitted sexually. (c) What are contraceptive devices ? Give two reasons for adopting contraceptive devices in humans. Q. 3) (a) A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it. (b) Why do stars twinkle ? Explain. (c) Write the function of each of the following parts of human eye : (i) Cornea (ii) Iris (iii) Crystalline lens (iv) Ciliary muscles (d) Why does the sun appear reddish early in the morning ? Will this phenomenon be observed by an astronaut on the Moon ? Give reason to justify your answer. Q. 4) (a) Define excretion. (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label the following organs of excretory system which perform following functions : (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out. Q. 5) Distinguish between esterification and saponification reactions with the help of the chemical equations for each. State one use of each (i) esters, and (ii) saponification process. Q. 6) State the cause of dispersion of white light by a glass prism. How did Newton, using two identical glass prisms, show that white light is made of seven colours ? Draw a ray diagram to show the path of a narrow beam of white light, through a combination of two identical prisms arranged together in inverted position with respect to each other, when it is allowed to fall obliquely on one of the faces of the first prism of the combination. Q. 7) a ) 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid. b) The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and write a chemical equation for its formation. List its two uses. Q. 8) Decomposition reactions require energy either in the form of heat or light or electricity for breaking down the reactants. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity. Q. 9) a) Mention any two components of blood. (b) Trace the movement of oxygenated blood in the body. (c) Write the function of valves present in between atria and ventricles. (d) Write one structural difference between the composition of artery and veins. Q. 10) i) You might have noted that when copper powder is heated in a china dish, the reddish brown surface of copper powder becomes coated with a black substance. (a) Why has this black substance formed ? (b) What is this black substance ? (c) Write the chemical equation of the reaction that takes place. (d) How can the black coating on the surface be turned reddish brown ? Ii) 2 g of ferrous sulphate crystals are heated in a dry boiling tube. (a) List any two observations. (b) Name the type of chemical reaction taking place. (c) Write balanced chemical equation for the reaction and name the products formed. Iii) In an industrial process used for the manufacture of sodium hydroxide, a gas ‘A’ is formed as a by-product. The gas ‘A’ reacts with lime water to give a compound ‘B’ which is used as a bleaching agent in the chemical industry. Identify ‘A’ and ‘B’. Also give the chemical equations of