QUESTION 14 TO 25 [ X SCIENCE SA II ] – SAMPLE PAPER 1
14. A real image,1/5 th the size of object is formed at a distance of 18 cm from a mirror. What is the nature of mirror ? Calculate its focal length.
15. A ray of light is incident obliquely on a glass slab. Draw a ray - diagram showing the path of the light ray. Clearly mark angle of incidence, angle of refraction, angle of emergence and lateral displacement of the ray. Give a formula to find refractive index of glass slab in terms of angle of incidence and angle of refraction.
16. A person cannot see objects farther than 12m from the eye clearly. Name the, defect of vision he is suffering from and the lens that should be used for correction of this defect Illustrate with the help of a diagrams, how this lens will correct the defective vision.
17. Give reasons for the following :
(a) Unsaturated hydrocarbons show addition reactions but not saturated hydrocarbons.
(b) Carbon only forms covalent compounds.
18. State modern periodic law. Mention the position of (i) hydrogen and (ii) isotopes of same element in the modern periodic table.
19. Distinguish between analogous organs and homologous organs. Identify the analogous and homologous organs amongst the following :
Wings of an insect, wings of a bat, forelimbs of frog, forelimbs of human.
20. Study the given data and answer the questions that follow :
(a) What is the term given to this type of cross ?
(b) What does the data in column 2 indicate ? State how did you arrive at this conclusion.
110- Round Green
102- Wrinkled Yellow
32- Wrinkled Green
21. Explain with the help of flow chart - “What determines the sex of a child genetically”
22. What is the importance of D.N.A copying in reproduction ? Why is variation beneficial to the species but not necessary for the individual ? Explain.
23. Draw a ray diagram in each of the following cases to show the formation of image, when the object is placed :
(i) between optical centre and principal focus of a convex lens
(ii) between F and 2F of a concave lens
(iii) At 2F of a convex lens
What can you say about sign and value of linear magnification ratio in, (i) and (ii) above.
OR
(i) Define real image of an object.
(ii) Name the mirror that
(a) can give real as well as virtual image of an object.
(b) will always give virtual image of same size of an object.
(c) will always give virtual and diminished image of an object.
(d) is used by a doctor in examining teeth.
(iii) With the help of a ray diagram explain the use of concave mirror as solar concentrators.
24. Complete the following reactions.
OR
(a) List two reasons for carbon forming a large number of compounds.
(b) An organic acid ‘X’ is a liquid which often freezes during winter time in cold countries. It has molecular formula C2H4O2. On warming with ethanol in the presence of a few drops of conc. H2SO4 a compound Y with sweet smell is formed.
(i) Identify X and Y
(ii) Write chemical equation for the reaction involved.
25. (a) What is the role of seminal vesicles and the prostate gland ?
(b) What are the three categories of contraception methods ? Write briefly about each.
OR
(a) Draw longitudinal section of a flower and label on it the following : (i) Ovary (ii) Style (iii) Stigma (iv) Anther
(b) Why is vegetative propagation practised for growing some plants ? Give two examples of plants grown by this method.
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