PART - A (PHYSICS)
I. Multiple choice questions: 2×1=2
1. The SI unit of resistivity is
(A) ohm-metre (B) coulomb
C) volt (D) joule
Ans: (A) ohm-metre
2. The distance between principal focus and the optic centre of the lens is
(A) Radius of curvature
(B) Object distance
C) Focal length
(D) Image distance
Ans: C) Focal length
II. Answer the following questions: 2×1=2
3. What does the thumb indicate in the right hand thumb rule ?
Ans: Direction of electric current
4. Mention the role of fuse in the domestic
circuit.
Ans: protecting appliances and wiring from
damage due to excess current, overloading, or short-circuiting.
III. Answer the following questions:3x2=6
5.
Write any two methods of increasing the magnetic field produced by a
circular coil carrying electric current.
Ans:
★increasing the electric current
★Increase the number of turns
6. If the total resistance in the given
circuit is 4Ω then find the resistance of the resistor X.
Ans:
Given Data:
Total Resistance (R total): 4Ω
Resistor 1 (R1): 6Ω
Resistor 2 (R2): 3Ω
Resistor (R3): X
1/Rp = 1/R1 + 1/R2
1/Rp = ⅙ + ⅓
1/Rp = 1+2/6
1/Rp = 3/6
Rp = 6/3
Rp = 2Ω
Rtotal = Rp + X
4Ω = 2Ω + X
X = 4Ω - 2Ω
X = 2Ω
7. Observe the given diagram and answer the
following questions:
a) What is the colour of the ray of light
indicated as A ?
b) Predict the colour of the ray of light
indicated as B. Justify your answer.
Ans:
★ A - Green, B - Green
★ There will be no dispersion
IV. Answer the following questions: 3x3=9
8. Draw the ray diagram of the image formed
when an object is placed at F1 in front of a convex lens. Mention the position
and size of the image.
Ans:
Position: At infinity
Size: highly enlarged
9. What is myopia (near sightedness ) ? What
are the causes for myopia ? Name the type of the lens used to correct myopia.
Ans:
★ The eye defect in which a person is able to see nearby objects clearly but not the distant objects.
★ causes
i) Excess curvature of eye lens.
ii) Elongation of the eyeball.
★ Correction
Using a concave lens of suitable power.
OR
a) What is the Tyndall effect ? Which property of the scattering particles decides the colour of the scattered light ?
b) What is the colour of danger signal lights
?
Ans:
a)
★ The phenomenon of scattering of a beam of
light by colloidal particles, when passed through a colloidal solution, is
called the Tyndall effect.
★ size of the scattering particles:
b) Red
10. A transparent glass sheet is placed over a bar magnet. Iron filings sprinkled over the glass sheet. The glass sheet is given a gentle tap and following observations are made.
a) Iron filings form non-parallel curved lines.
b) Iron filings are closely packed near the poles.
c) As moved away from the bar magnet, the distribution of the iron filings become rarer
Which property of the bar magnet does each of
the above observations indicate?
Ans:
a) shape of magnetic field lines.
b) magnetic field is strongest at the poles.
c) strength of the magnetic field decreases as the distance increases.
OR
The given diagram represents the experiment
conducted to observe the deviation of a beam of electrons when the beam enters
the magnetic field perpendicularly. If the beam deviates in the direction out
of the surface of the paper then
i) predict the pole of the magnet indicated as A
ii) state the principle that helps this prediction.
Ans:
★ A is the North Pole.
★ stretch the thumb, forefinger and middle
finger of your left hand such that they are mutually perpendicular. Forefinger
points in the direction of magnetic field and middle finger in the direction of
current, then the thumb will point in the direction of motion.
IV. Answer the following questions:2x4=8
11. a) What is magnification? If the magnification of the image produced by a lens is + 2, then mention the type of the lens.
b) Refractive index of medium A is lesser than the refractive index of medium B. Which of these two media is optically denser ? In which medium speed of light is more?
Ans:
a)
★ magnification is the ratio of the height of
the image to the height of the object.
/ m = h’/h
★ Convex Lens.
b)
★ Medium B is optically denser.
★ The speed of light is greater in Medium A.
OR
a) State two laws of reflection of light.
b) Write any two differences between concave mirror and convex mirror.
Ans:
a)
i) The angle of incidence is equal to the
angle of reflection.
ii) The incident ray, the normal to the mirror at the point of incidence and the reflected ray, all lie in the same plane
b)
12. a) State Ohm's law. List the factors on which the resistance of the conductor depends.
b) "The potential difference between two points of a conducting wire is 1 V." Write the meaning of this statement.
Ans:
a)
The potential difference V across the ends of a given metallic wire in an electric circuit is directly proportional to the current flowing through it at constant temperature.
Factors on which resistance of a conductor depends :
★ Length of a conductor
★ Area of cross-section of a conductor
★ Nature of the material
★ Temperature.
b)
1 Joule of work is done to move a charge of 1
Coulomb from one point to the other.
OR IV = 1j / 1C
PART - B (CHEMISTRY)
VI. Multiple choice questions: 3 x 1=3
13. Silver chloride turns grey colour when exposed to the sunlight. Because, silver chloride
(A) decomposes to form silver
B) splits as ions
(C) combines with oxygen
(D) reacts with atmospheric moisture
Ans: (A) decomposes to form silver
14. A + Salt solution of B → Salt solution of A + B. A and B in this word equation are metals. These metals respectively are
(A) copper and sodium
(B) lead and aluminium
(C) combines with oxygen
(D) magnesium and zinc
Ans: (D) magnesium and zinc
15. When CO2 gas is passed through a clear solution of X, this solution milky. When CO2 supply is continued, this milky solution turns clear solution due to the formation of salt Y. In this reaction X and Y IS
(A) Calcium carbonate and calcium hydroxide
(B) Calcium hydrogen carbonate and calcium chloride
(C) Calcium hydroxide and calcium hydrogen carbonate
(D) Calcium carbonate and calcium hydrogen carbonate
Ans: (C) Calcium hydroxide and calcium
hydrogen carbonate
VII. Answer the following questions: 3x1=3
16. What is amalgum ?
Ans: An Amalgam is an alloy of mercury with one or more other metals
17. Name the simplest hydrocarbon.
Ans: Methane / CH4
18. Correct the following incorrect electron
dot structure of an unsaturated hydrocarbon and rewrite,
VIII. Answer the following questions : 3x2=6
19. Draw the diagram to show the arrangement
of the apparatus used in the electrolytic refining of copper.
Ans:
20. Complete the given equation and name this
chemical reaction. Write one use of this reaction.
Ans:
★
★ It is used to convert liquid vegetable oils into solid vegetable ghee
21. Under a very high humid climate, sodium chloride with sulphuric acid produces a dry gas. Now which dry litmus paper changes its colour when brought in contact with this gas ? Why ?
Ans:
★ The dry blue litmus paper will turn red.
★ gas will dissolve in the atmospheric moisture absorbed by the paper forming Hydrochloric acid.
OR
A solution of baking soda is commonly applied
to the honey bee stung area. Justify this action.
Ans:
★ solution of baking soda is applied as it is a mild base
★ neutralises the action of acid.
IX. Answer the following questions : 3x3=9
22. What is rancidity ? Write any two methods of preventing rancidity.
Ans:
The process by which fat and oil substances are oxidized, changing their smell and taste, is called rancidity.
★ Adding antioxidants
★ Storing in airtight containers
★ Flushing gases like nitrogen into the packets
★ containing fried foods. (Any two)
23. Explain the formation of magnesium chloride molecule by the transfer of electrons.
Ans:
OR
a) Write any two differences between roasting and calcination.
b) Sodium metal is stored in kerosene.
Why ?
Ans:
a)
b) Sodium metal vigorously reacts with atmospheric oxygen and water, but not with kerosene.
24. Draw the diagram of the apparatus to
show the reaction of zinc granules with dilute sulphuric acid and testing
hydrogen gas by burning. Label the following parts. i) Delivery tube ii) Zinc
granules.
Ans:
X. Answer the following question : 1x4=4
25. a) Write the structures of the two structural isomers of butane.
b) Name the functional group present in the following carbon compounds:
i) Propanal
ii) Pentanol.
Ans:
a)
i) aldehyde / -CHO
ii) alcohol / - OH
OR
a) Explain the cleansing action of soap.
b) Carbon cannot form C4- ions or C4+ ions. Why ?
Ans:
a)
★ Soaps are sodium or potassium salts of long-chain carboxylic acids.
★ Soap molecules form micelles, in which the ionic end interacts with water and faces outside.
★ Carbon chain of the soap interacts with
oil or dirt.
★ This forms emulsion in water. The soap molecules pull out the dirt and wash the clothes clean.
b)
★ Carbon cannot form C4+ cation because of removal of 4 elections from a carbon atom would require a large amount of energy.
★ Carbon cannot form C4- anion because it
would be difficult for the nucleus with 6 protons to hold on to 10 electrons.
PART - C (BIOLOGY)
XI. Multiple choice questions. 3×1 = 3
26. The embryo gets nutrition from the mother's blood with the help of special structure called
(A) Fallopian tube
B) Ovary
C) Uterus
(D) Placenta
Ans: (D) Placenta
27. The generation in which Mendel performed cross pollination is
(A) Parent B) Ovary
C) F2 (D) F3
Ans: (A) Parent
28. A person runs immediately after seeing a snake, later experiences cramps in his leg muscles. Because, in the muscles
(A) carbon dioxide and ethanol will form
(B) pyruvate converts into lactic acid
(C) glucose is converted to pyruvate
(D) amount of oxygen increases
Ans: (B) pyruvate converts into lactic
acid
XII. Answer the following questions : 3×1 = 3
29. What is Photosynthesis ?
Ans:
Food preparation process in plants using carbon dioxide, water in presence sunlight and chlorophyll
30. A scientist cuts planaria as shown in
the figure below. After regeneration how many planaria will remain here ?
Ans: 3
Ans:
★ Excreting excess water in plants
★ Helping in the upward movement of water
XIII. Answer the following questions : 2×2 = 4
32. Name the enzyme present in saliva. Write its function.
Ans:
★ Salivary Amylase
★ It breaks down complex starch into simple sugars
OR
Name the following:
i) Structures that prevent the collapsing of air passage part of trachea in the human.
ii) Nitrogenous chemicals that are separated from the blood by the kidney.
Ans:
★ Rings of Cartilage.
★ Urea / Uric Acid
33. What is geotropism? Name the plant part that is positively geotropic.
Ans:
★ Growth of plant responce to gravity
★ Root
34. a) Define the following:
i) Food chain
ii) Biomagnification.
b) Mention the function of ozone layer in the atmosphere. Name the chemical responsible for ozone depletion.
Ans:
a)
i) a series of organisms in which food energy transfer.
ii) The increase in the concentration of harmful, non-biodegradable chemicals at each successive trophic level in a food chain.
b) It protects the Earth from harmful ultraviolet (UV) radiation from the sun.
35. Explain the role of chromosomes of father and mother in the determination of the sex of a child.
Ans:
★ One odd pair of sex chromosomes found in father. They are X and Y chromosomes. But, mother has only XX chromosomes.
★ The child received X haploid chromosome from father also receives X chromosome from mother, therefore XX pair of chromosome represents girl child.
★ The child received Y haploid chromosome from father, also receives X chromosome from mother, therefore XY pair of chromosome represents boy child.
OR
A pure tall pea plant (TT) is crossed with a pure short pea plant (tt). Express the result obtained in the F generation with the help of checker board. Write the phenotypic and genotypic ratio of the types of plants obtained in F2 generation.
Ans:
Genotypic ratio: 1 : 2 : 1
36. a) Heartbeat becomes faster at the time of anxiety. How does the body prepare to deal this situation ? Explain.
b) Experiencing taste and watering in the mouth automatically occurs by the memory of the food taste. Are both of these responses same ? Justify your answer.
Ans:
a)
★ Adrenaline is directly secreted into the blood. The blood to the skin is reduced due to contraction of muscles around small arteries.
★ The breathing rate increases because of the contractions of the diaphragm and the rib muscles. The heart beats faster, resulting in supply of more oxygen to the muscles
b)
★ No, both responses are not the same.
★ Tasting by memory is a voluntary response, while watering of the mouth is a reflex action.
37. Draw the diagram showing the schematic structure of the human heart.
Label the following parts: i) Septum i) Right atrium
Ans:
38. a) What is the function of the vas deferens and prostate gland in the male reproductive system ? How does the menstrual cycle occur in women ?
b) List the three methods of contraception that human beings usually follow.
Ans:
vas deferens: Transport sperm from testis.
prostate gland : They add their secretion to make the sperm transport easier and provide nutrition.
★ The uterus prepares itself every month to receive a fertilized egg and thus its lining becomes thick and spongy.
★ If the egg is not fertilized, the lining slowly breaks and comes out through the vagina as blood and mucous.
★ Barrier methods: Condoms, diaphragms.
★ Chemical methods: Oral pills
★ Surgical methods: Vasectomy , Tubectomy .
OR
a) What is the difference between self and cross pollination ? What are the changes that occur in a flower after fertilization ?
b) Mention any four advantages of vegetative propagation.
Ans:
a)
★ Self-pollination: Transfer of pollen from anther to stigma of the same flower or another flower on the same plant.
★ Cross-pollination: Transfer of pollen from anther of one flower to the stigma of a flower on a different plant of the same species.
★ Pollen grain enters the ovary through pollen tube and fuses with the ovum / egg. Zygote is formed.
★ Ovum develops into seed. Ovary grows rapidly and ripens into fruit.
★ Petals, sepals, stamen, style and stigma may shrivel and fall off.
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