PART - A (PHYSICS)
I. Multiple choice questions: 2×1=2
1. The instrument used to measure potential difference and its mode of connection in an electric circuit among the following is
(A) Ammeter, in series connection
(B) Voltmeter, in series connection
(C) Voltmeter, in parallel connection
(D) Ammeter, in parallel connection
Ans: (C) Voltmeter, in parallel connection
2. Observe the following table :
The correct conclusion related to the given lenses is
(A) A ; concave lens and B ; convex lens
(B) A ; convex lens and B ; concave lens
(C) Both are convex lenses
(D) Both are concave lenses
Ans: (B) A ; convex lens and B ; concave lens
II. Answer the following questions :
3. State the right hand thumb rule.
Ans:
Imagine you are holding a current carrying straight conductor in your right hand such that the thumb is pointing towards the direction of current. Then the fingers wrapped around the conductor give the direction of magnetic field.
4. Draw the symbol diagram of ‘Variable resistance (Rheostat)’ used in an electric circuit
Ans:
III. Answer the following questions :
5. List the factors on which the resistance of a conductor depends.
Ans:
★ Length
★ Area of cross section
★ Temperature
★ Nature of materials
6. Define the following :
i) Tyndall effect
ii) Dispersion of light.
Ans:
i) The scattering of a beam of light by colloidal particles.
ii) The splitting of white light into its component colors when passing through a prism.
7. Observe the given schematic diagram. What is the direction of force acting on the electron ? Justify your conclusion.
Ans:
★ Into the paper
★ According to Fleming’s Left-Hand Rule
★ current opposite to electron flow.
IV. Answer the following questions : 3×3=9
8. What is Myopia ? Mention the causes and remedy for this defect.
OR
Stars twinkle but planets do not twinkle. Why ?
Ans:
★Cannot see distant objects clearly.
Causes:
★ Decrease in focal length
★ Elongation of eyeball
Correction:
★ Concave lens
OR
★ Stars are point sources far away.
★ Planets closer to the earth than star.
★ Extended source of light from planets nullify the twinkling Effect.
9. How soft iron rod can be converted into an electromagnet using a solenoid ? How can the magnetic field of this electromagnet be increased ?
OR
Explain an activity for drawing the field lines around a bar magnet using a compass needle.
Ans:
★ Insert soft iron rod inside solenoid and pass current.
Increase strength by:
★ Increasing number of turns
★ Increasing current
OR
★ Take a small compass and a bar magnet. Place a magnet on a sheet of white paper fixed on a drawing board. Mark the boundary of the magnet.
★ Place the compass near the north pole of the magnet mark the position of two ends of the needle.
★ Now move the needle to a new position such that the south pole occupies the position previously occupied by its north pole.
★ In this way proceed step by step till we reach the south pole of the magnet. Join the points marked on the paper by a smooth curve. This represents field line.
★ Repeating above procedure we can draw as many lines as possible.
10. Draw the ray diagram that shows the image formed when an object is kept between 2F1 and F1 of a convex lens. Mention the size and position of the image.
Ans:
Position of the image-beyond 2F2
Size of the image: Enlarged
V. Answer the following questions :2×4=8
11. a) The refractive indices of water and ice respectively are 1·33 and 1·31. In which of these two medium the light travels faster ? Why ?
b) Explain why the emergent ray is parallel to the incident ray when light refracts through a rectangular glass slab.
OR
a) A pencil is partially immersed in water. Then the pencil appears to be bent.Explain this phenomenon.
b) Write any two differences between spherical mirror and spherical lens.
Ans:
a)
★ Light travels faster in ice
★ because lower refractive index
b)
★ because the opposite faces of a rectangular glass slab are parallel,.
★ Due to this the refractive index change is equal and opposite at the two parallel air-glass and glass-air interfaces.
OR
a)
The extent of bending of the ray of light at the opposite parallel faces AB (air-glass interface) and CD (glass-air interface) of the rectangular glass slab is equal and opposite. This is why the ray emerges parallel to the incident ray.
b)
Spherical Mirror:
★ Reflects light
★ Concave/Convex mirror
★ 1/v + 1/u = 1/r
Spherical Lens:
★ Refracts light
★ Concave/Convex lens
★ 1/v - 1/u = 1/f
12. Observe the circuit given below. Find the total resistance, total current and power in the circuit.
Ans:
( CHEMISTRY )
VI. Multiple choice questions: 3×1=3
13. A compound that reacts with an acid and a base to produce salt and water is
(A) Aluminium oxide
(B) Copper oxide
(C) Iron oxide
(D) Sodium oxide
Ans: (A) Aluminium oxide
14. Compound that forms by the reaction between carboxylic acid and alcohol is
(A) an aldehyde
(B) a ketone
(C) a haloalkane
(D) an ester
Ans: (D) an ester
15. Observe the following equations and identify the correct statement with respect to these equations
(A) Copper is more reactive than iron and silver
(B) Iron is more reactive than copper and silver
(C) Copper is more reactive than silver but less reactive than iron
(D) Silver is more reactive than copper and iron
Ans: (C) Copper is more reactive than silver but less reactive than iron
VII. Answer the following questions : 3×1=3
16. What is rancidity ?
Ans: The process of oxidation of fats and oils in food, resulting in an unpleasant smell and taste.
17. Write the chemical formula of baking soda.
Ans: NaHCO3
18. Identify the homologous series among the following.
Ans: Series - 1
VIII. Answer the following questions :
19. What is catenation ? Name the simplest hydrocarbon.
Ans:
★ The unique ability of carbon atoms to form bonds with other atoms of carbon, giving rise to large molecules.
★ Methane
20. How is pure mercury obtained from cinnabar ?
OR
Why fire does not catch up when calcium reacts with water ?
Ans:
★ cinnabar is heated in air, it is first converted into mercuric oxide (HgO).
★ Mercuric oxide is then reduced to mercury on further heating. /
★ The reaction of calcium with water is less violent.
★ The heat evolved is not sufficient for the hydrogen to catch fire
21. Analyse the activity depicted in the figure given below. In this activity, when ferrous sulphate crystals are heated does the colour and crystalline nature of it remain same or not ? Support your answer with reason.
Ans:
★ colour and crystalline nature change.
★ due to loss of water of crystallisation
IX. Answer the following questions :
22. Translate the following word equations into chemical equations :
i) Carbon + Oxygen → Carbon dioxide
ii) Zinc carbonate → Zinc oxide + Carbon dioxide
iii) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
OR
Chemical reactions are to be balanced. Why ? Which are the observations that help us to determine that chemical reaction has taken place ?
Ans:
i) C + O2 → CO2
ii) ZnCO3 → ZnO + CO2
iii) Ca(OH)2 + CO2 → CaCO3 + H2O
OR
★ change in colour
★ evolution of a gas
★ change in temperature.
★ change in state.
23. Draw the diagram of the arrangement of the apparatus used to show the action of steam on metal. Label the following parts. i) Delivery tube ii) Metal sample.
Ans:
24. a) By using distilled water and concentrated acid, how do you decrease the concentration of the acid ? Explain.
b) Doctors suggest to take milk of magnesia at the time of indigestion. Why?
Ans:
★ Always add acid to water slowly with constant stirring.
★ Adding water to concentrated acid can cause the mixture to splash out and cause burns due to the highly exothermic nature.
b)
★ It is a mild base /antacid that neutralizes the excess hydrochloric acid produced in the stomach.
X. Answer the following questions :1×4 =4
25. a) Carbon atoms neither form C4- anion nor form C4+ cation. Explain.
b) Write the structural formula of ‘Butyne’ and ‘Cyclohexane’.
OR
a) Explain the cleansing action of soap.
b) Write the differences between saturated and unsaturated carbon compounds.
Ans:
a)
★ 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.
b)
Butyne:
Cyclohexane:
OR
a)
★ The molecule of soaps are sodium or potassium salts of long chain carboxylic acids.
★ Ionic end of soap interacts with water while the carbon chain interacts with oil
★ Soap molecule thus forms a structure called micelle. This forms an emulsion in water.
★ The micelles thus help in pulling out the dirt in water.
b)
PART – C
( BIOLOGY )
26. The blood vessel that carries oxygenated blood from the heart is
(A) Pulmonary vein
(B) Superior venacava
(C) Aorta
(D) Pulmonary artery
Ans: (C) Aorta
27. The group of organisms that reproduce by fission only, is
(A) Amoeba, Hydra, Spirogyra
(B) Leishmania, Amoeba, Yeast
(C) Amoeba, Plasmodium, Planaria
(D) Plasmodium, Amoeba, Leishmania
Ans: (D) Plasmodium, Amoeba, Leishmania
28. Observe the structure given in the following figure. The type of tropic
movement that helps the movement of ‘C’ towards ‘B’ here is,
(A) Phototropism
(B) Chemotropism
(C) Geotropism
(D) Hydrotropism
Ans: (B) Chemotropism
XII. Answer the following questions:3×1=3
29. What is heredity ?
Ans: The transmission of characters from parent to their off springs.
30. Observe the following figures. Which figure represents low rate of gaseous
exchange ? Why ?
Ans: Figure (a) represents a low rate of gaseous exchange because the stomatal pore is closed.
31. Observe the processes depicted in the given figures. Among the progenies, which of the process (i) causes variations ? (ii) causes similarities ?
(i) Variations: Figure 2
(ii) Similarities: Figure 1
XIII. Answer the following questions:2x2=4
32. a) What is reflex arc ?
b) Which hormones are responsible for sexual maturation in human beings ?
OR
a) What is the function of neuron ( nerve cell )?
b) Which hormones are responsible for the growth of stem in plants and wilting of leaves ?
Ans:
a) The pathway of nerve impulses in a reflex action.
b)
★ Testosterone in male
★ Oestrogen in female
OR
a) Conducting information via electrical impulses from one part of the body to another.
★ Gibberellin: growth of stem
★ Abscisic acid : wilting of leaves
33. Draw the diagram showing the structure of nephron.
Ans:
XIV. Answer the following questions : 3 × 3 = 9
34. Tall pea plant ( TT ) is hybridised with a short pea plant ( tt ). Express the results obtained in the F2 generation with the help of checker board and write the ratio of the types of plants obtained.
OR
a) How is the sex of a child determined in human beings ? Explain.
b) Write the difference between dominant and recessive hereditary traits.
Ans:
Phenotypic ratio: 3:1, (3 tall, 1 dwarf)
Genotypic ratio: 1:2:1, (1 pure tall, 2 impure tall,1 pure dwarf)
OR
a)
★ Woman has a perfect pair of sex chromosomes, both called X. bat.
★ Man has a normal sized chromosome X and another short sized chromosome Y.
★ A child who inherits X chromosome from her father will be a girl
★ a child who inherits Y chromosome from his father will be a boy. /
b)
Dominant traits:
★ The trait which appears in the F1 progeny
★ More in number
Recessive traits:
★ The trait not appear in the F1 progeny.
★ Less in number
35. Observe the following picture of trophic levels and answer the questions given below :
i) Organisms of which trophic level have more concentration of harmful chemicals ? Why ?
ii) Zoo planktons have more energy than the large fish. How ?
Ans:
i)
★ T5 / (Eagle)
★ Due to Biological Magnification.
ii) Energy decreases by 90% at each subsequent level / 10% Law.
35. Draw the diagram showing the structure of human brain. Label the following parts : i) Pons ii) Cerebrum.
Ans:
XIV. Answer the following questions : 3×3=9
37. a) Name the transporting tissues in plants. Write their function.
b) Write any four methods used by the plants to eliminate waste materials.
OR
a) Name the following :
i) The site of complete digestion of food in human digestive system
ii) The organ that secretes bile juice.
b) What is anaerobic respiration ? Write the products of this respiration.
Ans:
a)
Xylem: transports water and minerals.
Phloem: Transports food.
b)
★ Waste products are stored as resins and gums in old xylems.
★ Through withering / wilting / shedding of leaves
★ Excrete some waste substances into the soil around them
★ Excess of water by transpiration
★ Oxygen by photosynthesis
★ Carbon dioxide by respiration ( Any four points )
OR
a)
i) Small intestine
ii) Liver
b)
★ Respiration in the absence of oxygen.
★ Products: Ethanol, CO2, and Energy.
XVI. Answer the following questions : 1×5=5
38. a) How does an egg in a female develop into a foetus in the uterus ? How does embryo get nourishment in the mother’s womb ? Explain.
b) Write the function of testes in human male reproductive system.
OR
a) Write any four advantages of vegetative propagation.
b) What is pollination ? What are the changes that occur in a flower after fertilisation?
Ans:
a)
★ The fertilised egg ( Zygote ) starts dividing and forms an embryo.
★ The embryo is implanted in the lining of the uterus.
★ It continues to grow and develop organs to become foetus.
Nourishment :
★With the help of a special disc shaped tissue called placenta.
★ It contains villi on the embryo’s side and blood spaces on the mother’s side.
★This provides glucose and oxygen to the developing embryo.
b) Production of sperms and secretion of testosterone.
OR
a)
b)
★ The transfer of pollen from the stamen to the stigma.
Germination of the pollen : Pollen tube develops.
★ Fertilization : 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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