Science
1. Out of
the three elements P, Q and R having atomic numbers 11, 17 and 19 respectively
which two elements will show similar properties and why ?
2. Why do
mice whose tails were surgically removed just after birth for generations,
continue to produce mice with tails ?
3. List two
causes of pollution of river Ganga.
4.Define
multiple fission. Give its one example.
5. The
linear magnification produced by a spherical mirror is –1. Analysing this value
state the (i) type of mirror and (ii) position of the object with respect to
the pole of the mirror. Draw ray diagram to justify your answer.
6. Suppose
you find a heap of domestic waste, in a nearby park, which is decomposing. What
would you do to make the people of the surrounding area realise that such type
of disposal of domestic waste is harmful to the environment ?
7. List four
advantages of water stored in the ground
8.Write the
respective chemical equations to show what happens when
(i)methane
is burned in presence of oxygen ?
(ii)ethanol
is heated with concentrated sulphuric acid at 443 K ?
(iii)ethanol
reacts with ethanoic acid in the presence of an acid acting as a catalyst ?
9 Write the chemical equation to explain what
happens when ethanol is heated with alkaline solution of potassium
permanganate. Mention two physical properties and two uses of ethanol.
10 Write the
number of groups and periods in the modern periodic table. Mention the criteria
of placing elements in the (i) same group and (ii) the same period. Illustrate
your answer with an example for each case.
11. Study the
following table in which positions of six elements A, B, C, D, E and F are
shown as they are in the modern periodic table :
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Group
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1
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2
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3 – 12
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13
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14
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15
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16
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17
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18
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Period ¯
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2
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A
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B
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C
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3
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D
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E
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F
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(i) Name the element which will form only
covalent compounds.
(ii) Which
element is a metal with valency one ?
(iii) Which
element is a non-metal with valency two ?
(iv) Out of
D and E, which has a bigger atomic radius and why ?
(v) Write
the formula of the compound formed when B combines with D.
12. List three main factors responsible for the rise of a new species giving a brief description about each.
13. Explain Mendel’s experiment with peas on inheritance of characters, considering only one visible contrasting character.
14. On the
notice board of ultrasound clinics it is generally stated. ‘‘Here prenatal sex
determination and disclosure of sex (boy or girl before birth) of foetus is not
done. It is prohibited and punishable under law.’’
(a) List two advantages of imposing ban on
prenatal sex determination.
(b) What can students do to educate the
society about the following ?
(i) The ill-effects of indiscriminate
female foeticide
(ii) Adopting small family norms
15. concave
mirror of focal length 15 cm. What should be the range of distance of the
candle flame from the mirror ? State the nature and size of the image he is
likely to observe. Draw a ray diagram to show the image formation in this case.
16. The image of
a candle flame placed at a distance of 40 cm from a spherical lens is formed on
a screen placed on the other side of the lens at a distance of 40 cm from the
lens. Identify the type of lens and write its focal length. What will be the
nature of the image formed if the candle flame is shifted 25 cm towards the
lens ? Draw a ray diagram to justify your answer.
17. What is a
spectrum ? How can we recombine the components of white light after a glass
prism has separated them ? Illustrate it by drawing a diagram.
18. What is meant
by food chain ? ‘‘The number of trophic levels in a food chain is limited.’’
Give reason to justify this statement.
19. List in tabular form the
two differences between asexual and sexual mode of reproduction. Name and
explain with the help of labelled diagram the process by which Hydra reproduces
asexually.
20.
(a)Name the human male reproductive organ that produces sperms and also secretes hormones. Write the functions of the hormone secreted.
(a)Name the human male reproductive organ that produces sperms and also secretes hormones. Write the functions of the hormone secreted.
(b) Name the parts of the
human female reproductive system where
(i) fertilization and (ii)
implantation occur respectively. Explain how the embryo gets nutrition inside
the mother’s body.
21. What is meant by power of a lens ? Name and define its S.I. unit. One student uses a lens of focal length +50 cm and another of –50 cm. State the nature and find the power of each lens. Which of the two lenses will always give a virtual, erect and diminished image irrespective of the position of the object ?
22. What is
myopia ? List two causes for the development of this defect. How can this
defect be corrected using a lens ? Draw ray diagrams to show the image
formation in case of (i) defective eye and (ii) corrected eye.
23. What are
hydrocarbons ? Distinguish alkanes from alkenes and each of them from alkynes,
giving one example of each. Draw the structure of each compound cited as
example to justify your answer.
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