14. (a) Which mirror do we use as a rear view mirror in vehicles ?
(b) Draw a ray diagram to illustrate the formation of an image when an object is placed anywhere in front of the mirror on its Principal Axis. State the nature and position of the image formed.
15. (a) Define dispersion of light.
(b) Draw a ray diagram to show the path of a light ray that enters the glass prism obliquely. Label on it the angle of incidence and angle of deviation.
16. A convex lens of focal length 2O cm is placed at a distance of 24 cm from the screen. How far from the lens should an object be placed so as to form a real image on the screen ? Also find the nature and magnification produced by the lens.
17. (a) Define the term Functional group. Identify the functional group present in the following compounds : O
||
(i) CH3 – CH2 – CH2 – OH (ii) H – C – H
(b) What will you observe on adding a 5% alkaline potassium permanganate solution drop by drop to some warm ethanol taken in a test tube ? Write the name of the compound formed during the above chemical reaction.
18. Given below are four elements with their atomic numbers
Element Atomic number
A 16
B 11
C 3
D 14
(a) Identify the elements which belong to the qsame group of the Modern Periodic table.
(b) Arrange the given elements in decreasing order of atomic size.
(c) Write the formula of the oxide of B.
(d) Which of the above elements is a metalloid ?
19. What are fossils ? List two ways by which we can estimate the age of fossils.
20. What are sex chromosomes ? What role do they play in determining genetically the sex of an individual in human beings ?
21. Why are some pea plants tall and others short in nature ? Explain with reference to the role of genes in controlling characteristics.
22. In the diagram of human male reproductive system given below :
(a) Label parts A and B.
(b) Name the hormone produced by organ ‘X’. What is the role of this hormone in the human male ?
(c) Mention the name of substances that are transported by tubes
(i) C and (ii) D
23. (a) Define 1 dioptre of power. Find the focal length of a lens of power -2.0 D.
(b) Why does a lemon kept in water in a glass tumbler appear to be bigger than its actual size ?
(c) Study the table given below and state the medium in which light ray will travel fastest. Why ?
Medium A B C
Refractive Index 1.33 1.5 2.4
OR
(a) State the laws of refraction.
(b) What is meant by the term absolute refractive index ? The speed of light in a transparent medium is 0.6 times that the speed in vacuum. Find refractive index of the medium.
(c) How should a ray of light be incident on a rectangular glass slab so that it comes out from the opposite side of the slab without being displaced ? Draw a ray diagram to illustrate your answer.
24. (a) Write a chemical equation for the combustion of Ethanol.
(b) List any two differences between saturated and unsaturated carbon compounds.
(c) Draw the structures of any two isomers of butane and name them.
OR
(a) Draw the structure of Ethyne (C2H2).
(b) Define Esterification. Write a chemical equation to illustrate it.
(c) List any two differences between soaps and detergents.
25. (a) Name the female reproductive part of a flower. Draw diagram of its longitudinal section depicting the process of fertilization of pollen on stigma and label on it the following :
(i) male germ cell (ii) female germ cell (iii) Ovary
(b) What happens to the following parts after fertilization ?
(i) ovum (ii) ovary (iii) ovule (iv) sepals and petals
OR
(a) Draw a neat diagram of the reproductive system of a human female and label on it the following :
(i) reproductive part that produces the female hormone
(ii) site of fertilization
(iii) organ where growth and development of the embryo takes place.
(b) How does the growing embryo meet with its nutritional requirements ?
(c) What happens if the ovum is not fertilized ?
(d) Mention a contraceptive method that can be used by the human female.
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