02 Board Answer Paper October 2014

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Science and Technology

BOARD ANSWER PAPER : OCTOBER 2014 SCIENCE AND TECHNOLOGY SECTION A 1.

(A)

(a)

(b)

Fill in the blanks and rewrite the statemetns: i. Elements showing properties of both metals and non-metals are known as metalloids. ii. The device used for producing current is called a generator. Rewrite the following table so as to match second and third column with first column: Column I (i) Myopia (ii) Presbyopia

(c) (B)

2.

[1] [1]

Column II b. Near-sightedness a. Old age problem

Column III 2. Concave lens 1. Bifocal lens

[1] [1]

State whether the following statements are True or False: True

[1]

Choose the correct alternative and rewrite the following sentence: i. (C) Phenolphthalein is Synthetic type of Indicator.

[1]

ii.

(B)

Litmus paper is not required to find the pH of a given solution.

[1]

iii.

(B)

When the resistance of the conductor increases, then the current will decrease.

[1]

iv.

(A)

If three resistors 2 ohm, 3 ohm and 4 ohm are connected in series, then effective resistance in a circuit will be 9 ohm. [1]

v.

(D)

A ray of light strikes the glass slab at an angle of 50. The the angle of incidence will be 40. [1]

Answer the following questions (any five): i Mendeleev’s Periodic law states that “The physical and chemical properties of elements are periodic function of their atomic masses.” [2] ii.

Hydrogen and Sodium are the two elements which have a single electron in their outermost shell. [2]

iii.

a. b. c.

iv.

Grills of doors and windows are generally made up of iron metal. Before painting, iron metals are in direct contact with the moisture in atmosphere. Thus chemical reaction between iron and oxygen from air takes place to form a reddish brown coloured substance (ferric oxide) called rust which damages the grill. d. Painting prevents corrosion as it prevents iron metal from coming in contact with moisture and oxygen from the atmosphere. Hence, grills of doors and windows are always painted before they are used. a.

b.



[½] [½] [½] [½]

The incident ray and the refracted ray are on the opposite side of the normal at the point of incidence, and all three lie in same plane. [1] For a given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. If ‘i’ is the angle of incidence and ‘r’ is angle of refraction, then sin i = constant sin r This constant is called the refractive index of second medium with respect to first medium. It is denoted by . sin i = . [1] sin r 1

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Board Answer Paper: October 2014

A B P

i

N

Q Glass slab

Refracted ray S

R Me C D

Refraction of light through a glass slab

vi. 3.

Cholera and Jaundice are two human diseases caused due to water pollution.

[2] [2]

Answer the following (any five): i. a. The slow process of decay or destruction of a metal due to the effect of air, moisture and acids on it is known as corrosion. [1] b. No, gold ornaments do not corrode because gold is a noble metal (inert) and thus, it does not react with acids, moisture and air. [2]

ii.

a. b. c.

iii.

Following safety measures should be followed while using electricity: a. Wires carrying electricity should not be touched bare footed. b. While working with electricity, one must wear gloves made up of insulated material and rubber sole shoes. c. The insulation of the wire must be checked periodically. d. The electrical appliances must be earthed. e. Electric circuits should be switched off during lightning. f. An electric fuse is a very safety device. Electric fuse of proper rating should be used to stop the flow of excess electric current and to save the electrical appliances. g. For avoiding overloading, many appliances should not be connected at a time in the circuit. [Any three - 1 mark each]

iv.

a. b. c.

v.

a.

vi.

2

Solution ‘C’ is acidic. Solution ‘A’ is basic. Solution ‘B’ is neutral.

[1] [1] [1]

The phenomenon of splitting of light into its component colours is called dispersion of light. [1] The band of coloured components of a light beam is called its spectrum. [1] Various colours obtained in spectrum of light are in the sequence – Violet, Indigo, Blue, Green, Yellow, Orange and Red. [1]

b.

Principle of electric motor: Electric motor works on the principle that a current carrying conductor placed in a magnetic field experiences a force. [1½] Principle of electric generator: Electric Generator works on the principle of electromagnetic induction. When the coil of electric generator rotates in a magnetic field. Magnetic field induces a current in this coil. This induced current then flows into circuit connected to the coil. [1½]

a. b. c. d.

Citizens should plant trees and develop gardens, parks and open grounds in locality. Citizens should save fossil fuels and reduce pollution. They should minimize electricity consumption. They should use public transport instead of private vehicles.

Target Publications Pvt. Ltd. e. f. g.

4.

Science and Technology

Citizens should use non conventional source of energy like solar, wind energy, tidal energy. They should maintain vehicles in well tuned condition. Citizens should keep home and public places clean and should keep their own locality free from pollution. [Any three efforts - 1 mark each]

Answer any one of the following questions: (A) (a) I should choose Resistors in parallel for decreasing resistance in a circuit. i. ii. Ebonite for getting protection from electric current. iii. Ammeter to measure the current in the circuit.

(b)

i. ii. iii. iv.

(B)

(a)

i. ii. iii.

(b)

[1] [1] [1]

When electrician was called, he found that circuit caught fire due to short circuit. He observed that live wire and neutral wire came in direct contact which resulted in short circuit. Because of short circuit resistance of the circuit became very small and hence huge amount of current flew through it. It ultimately produced large amount of heat and raised the temperature. As a result circuit caught fire. Concave mirror is found in torches, headlights, flood lights, solar devices, dentist’s mirror. Convex lens is used in simple microscope, compound microscope, telescopes, optical instruments and spectacles. Reflecting mirrors are used in projector lamps.

[½] [½] [½] [½] [1] [1] [1]

i. ii. iii. iv.

The power of accommodation of eye usually decreases with ageing. Some aged people suffer both myopia and hypermetropia. To correct this defect bifocal lens is used. In bifocal lens upper part is concave lens to correct myopia and lower part is convex lens for near vision. Hence grandfather uses bifocal lens in his spectacle. [2] SECTION B

5.

(A)

(a)

(b)

(B)

6.

Fill in the blanks and rewrite the statements: i. The general formula of Alkane is CnH2n+2. ii. Liver is the largest gland in the body. iii. The loss of water from the plants is known as transpiration.

[1] [1] [1]

State whether the following statements are True or False: i. True. ii. True.

[1] [1]

Choose the correct alternative and rewrite the following : i. (B) Ethanoic acid has a pungent smell.

[1]

ii.

(D)

All of the above are mode of asexual reproduction.

[1]

iii.

(B)

In hydra the type of reproduction is Budding.

[1]

iv.

(A)

Oxygen is not essential for photosynthesis.

[1]

v.

(C)

Ankita bought some Glucose Powder. She felt it was adulterated with starch powder. She would test it by iodine test. [1]

Answer the following subquestions (any five): i. a. Sodium is one of the most reactive metals.

b.

[½]

Sodium reacts with oxygen in air, at room temperature, to form sodium oxide. 4Na + O2  2Na2O

[½] 3

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ii.

Board Answer Paper: October 2014

c.

Sodium reacts with water (moisture) to evolve hydrogen which immediately catches fire producing lot of heat. [½] 2Na + 2H2O  2NaOH + H2 + Heat energy

d.

Sodium does not react with kerosene and sinks in it. So storing the sodium under kerosene prevents its contact with air. [½]

a.

Organic compounds containing only hydrogen and carbon in their structure are known as hydrocarbons. [1] Examples. Ethene, Methane [1]

b. iii.

Autotrophic nutrition It is the mode of nutrition in which organisms produce their own organic food. b. Organisms producing their own food are known as autotrophs. c. Autotrophs use simple inorganic substances present in the surroundings to produce food. Eg. Plants

a.

Heterotrophic nutrition It is the mode of nutrition in which organisms depend on other organisms for their food. Organisms depending on others for food are known as heterotrophs. Heterotrophs depend on other organisms to get their food. Fungi

[½] [½] [½] [½]

iv. Gall bladder

[2]

Common duct Liver

7.

v.

a. b.

The process of transfer of pollen grains from anther to stigma is called pollination. There are two types of pollination: self pollination and cross-pollination

[1] [1]

vi.

a. b.

Heredity is the transmission of physical or mental traits from parents to offsprings. Examples: Attched ear-lobes , Rolling tongue.

[1] [1]

Answer any five of the following subquestions: i. Three methods of preventing rusting of iron: a. Galvanizing: It is a process of giving a thin coating of zinc on iron or steel to protect them from corrosion. Eg. shiny iron nails, pins etc. b. Rusting of iron can be prevented by coating it with paint or oil. c. Rusting of iron can be prevented by coating it with greese or varnish. ii. Positive carbon anodes

[1] [1] [1]

+  Alumina + Cryolite + Fluorspar

Aluminium

Negative carbon cathode

Aluminium outlet Steel container Extraction of aluminium 2 At anode: 2O  O2 + 4e 4

[2] [1]

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An atom or a group of atoms present in the molecule which determines the characteristic property of organic compounds is called functional group. [1] a. Ethyl alcohol contains functional group (OH) [1] b. Acetaldehyde contains functional group (CHO). [1]

iv.

a. b. c. d. e. f.

v.

Growth-independent movement in plants: a. The movement of plants which do not result in their growth are known as growth independent movement of plants. [1] b. There are many plants which show growth independent movements. Eg. In case of Mimosa, movement is in response to the stimulus of touch. c. This information of touch is transferred by means of electrical and chemical signals from one cell to another. d. Then the movement is brought about as the plant cells change their shapes by altering the amount of water in them. e. The cells either swell or shrink and thus, change their shapes. [1] f. Some growth-independent movements seen in plants are  lotus flowers open in the morning and the tuberose, at night; the tentacles on the leaves of the insectivorous plants like drosera curl inwards at the touch of an insect etc. [1]

vi.

a. b.

8.

Science and Technology

Coughing  Involuntary Food getting digested  Involuntary Moving a table  Voluntary Beating of heart  Involuntary Functioning of kidneys  Involuntary Flying a kite  Voluntary

[½] [½] [½] [½] [½] [½]

Vegetative propagation is the form of asexual reproduction in which new plants are produced from the vegetative parts, i.e. root, stem, leaves and buds of the plant. [1] Potato develop from eyes i.e. buds [1] Bryophyllum reproduces from the buds on the leaf margin. [1]

Write the answer of any one question given below: i. a. There are 22 pairs of autosomes and one pair of sex chromosome present in human beings. b. In females 22 pairs of autosomes and XX sex chromosomes are present. c. In males 22 pairs of autosomes and XY sex chromosomes are present. d. In human males, two dissimilar chromosomes are present in the 23rd pair, the longer ‘X’ and the shorter ‘Y’. In females, the 23rd pair contains two similar ‘X’ chromosomes. All children inherit one ‘X’ chromosome from their mother.The other chromosome is inherited from the father. If the chromosome inherited from the father is ‘X’, then the offspring is a daughter and if it is ‘Y’, then the offspring is a son. Thus, the sex of the child is determined by the male sex chromosome.

ii.

Powers of the MPCB to control water and air pollution: a. Implementation of environmental laws and pollution control. b. Laying down standard and securing their compliance. c. Inspection and monitoring of all sources of pollution. d. Issuance of notices with time limit to comply with the legal requirements. e. Closure of the defaulter unit in grave cases, Prosecution in cases of serious violation.

[2] [1] [1]

[1] [1] [1] [1] [1] [1]

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