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# Board Paper of Class 10 2015 Science - Solutions

(PART – A)
General Instructions:
(i) There are 50 objective type (MCQ) questions is Part - A and all the questions are compulsory.
(ii) The questions are serially numbered from 1 to 50 and each carries 1 mark.
(iii) Read each question, carefully, select proper alternative and answer in the O.M.R. sheet.
(iv) The OMR sheet is given for answering the questions. The answer of each question is represented by (A) , (B) , (C) , (D) Darken the circle of the correct answer with ball-pen.
(v) Set No. Of Question Paper printed on the upper-most right side of the Question Paper is to be written in the column provided in the OMR sheet.

(PART – B)
General Instructions:
1) Write in clear hand writing.
2) There are four sections in part –B of the question paper and total 1 to 18 questions are there.
3) All the questions are compulsory. Internal options are given.
4) The numbers at right side represent the marks of the questions.
5) Start new section on new page.
6) Maintain sequence.

SECTION-A
Questions from 51 to 55 are short answer type of questions. Write an answer to each using maximum 30 words. Each question carries 2 marks.
SECTION-B
Questions from 56 to 60 are short answer type of questions. Use maximum 30 words to answer them. Each question carries 2 marks.
SECTION-C
Questions from 61 to 65 are short answer type of question. Write an answer to each using maximum 50 words. Each question carries 3 marks.
SECTION-D
Question numbers 66 to 68 are to be answered in detail using nearly 100 words. Each question carries 5 marks.
• Question 1
What is the general formula of alkyne series?

(A) CnH2n

(B) CnH2n–2

(C) CnH2n+2

(D) CnHn VIEW SOLUTION
• Question 2
Which of the primary state in transformation of coal?

(A) Peat

(B) Lignite

(C) Bitumen

(D) Anthracite VIEW SOLUTION
• Question 3
From where mineral coal is obtained in Gujarat?

(A) Ankleshwar

(B) Khambat

(C) Thangadh

(D) Kalol VIEW SOLUTION
• Question 4
What is the angle between any two bonds in methane molecule?

(A) 105°54’

(B) 109°28’

(C) 119°28’

(D) 190°28’ VIEW SOLUTION
• Question 5
What is prepared by Fisher-Tropsch method?

(A) Acetone

(B) Acetic acid

(C) Acetaldehyde

(D) Ethanol VIEW SOLUTION
• Question 6
Which of the following monomers is in polythene?

(A) CH3 – CH3

(B) CH2 + CH = CH – CH3

(C) CH = CH

(D) CH2 = CH2 VIEW SOLUTION
• Question 7
Why does one who drinks alcohol get tempted to drink more alcohol?

(A) because CO2 increases in liver

(B) because Formaldehyde increases in liver

(C) because amount of enzyme P-450 increases in liver

(D) because amount of disulphiram increases in liver VIEW SOLUTION
• Question 8
What is the length of small intestine in an adult human being?

(A) 3.5 m

(B) 6.5 m

(C) 4.5 m

(D) 2.5 m VIEW SOLUTION
• Question 9
How many uriniferous tubules are there in each kidney?

(A) 10 lakhs

(B) 20 lakhs

(C) 30 lakhs

(D) 1 lakh VIEW SOLUTION
• Question 10
Which of the following structure is responsible for transportation of water in higher plants?

(A) Sieve tube

(B) Sieve cell

(C) Vessel

(D) Companion cell VIEW SOLUTION
• Question 11
By what name is the liquid medium of blood known as?

(A) Plasma

(B) Blood particles

(C) Waste (excretory) substances

(D) Waste material VIEW SOLUTION
• Question 12
Where are the waste products stored in plants?

(A) In Plant cells

(B) In Cytoplasm

(C) In Phloem cell

(D) In Cellular Vacuoles VIEW SOLUTION
• Question 13
Which of the following pairs is not true?

(A) Testosterone-Testes

(B) Adrenaline-Pituitary gland

(C) Pancreas-Insulin

(D) Progesterone-Ovary VIEW SOLUTION
• Question 14
Cerebellum, medulla oblongata and pons are the part of ________________.

(A) mid-brain

(B) hind-brain

(C) fore-brain

(D) spinal cord VIEW SOLUTION
• Question 15
Which of the following are the true methods of artificial propagation?

(A) Fission and Budding

(B) Layering, Cutting, Budding

(C) Cutting, Layering, Grafting

(D) Cutting, Grafting, Budding VIEW SOLUTION
• Question 16
How many Chromosomes are there in human ovum?

(A) 46

(B) 64

(C) 23

(D) 32 VIEW SOLUTION
• Question 17
Which of the following organs are not the homologous organs?

(A) Forelimb in human and lizard

(B) Forelimb in lizard and frog

(C) Wings of bat and birds

(D) Wings of butterfly and bat VIEW SOLUTION
• Question 18
The human species have genetic roots in ____________.

(A) India

(B) America

(C) Africa

(D) Australia VIEW SOLUTION
• Question 19
What is famous for the constructive and functional unit?

(A) Ecosystem

(B) Food chain

(C) Food web

(D) None of these VIEW SOLUTION
• Question 20
Chlorine is the main factor to damage Ozone layer. CFC is considered responsible for 80% of total decrease in Ozone layer.
If the pollution in the atmosphere increases, which of the following is possible in future?
P. The ice at poles will melt and all the organisms will die living at the island.
Q. Many organisms living at island may migrate.
R. The existence of forests on the Earth will be no more.

(A) Only Q

(B) Only P and Q

(C) All P, Q and R

(D) Only Q and R VIEW SOLUTION
• Question 21
Names of endangered plant species are published in ________________.

(A) Endangered species book

(B) Green data book

(C) Red data book

(D) Yellow data book VIEW SOLUTION
• Question 22
One day the contractor’s workers appeared in the forest to cut the trees but the men folk were absent. However, the women from the village reached the forest quickly and elapsed the tree trunks preventing the workers from felling the trees. Thus, the forest trees were saved. The incident was originated in a remote village called “Reni” in Garhwal in the early 1970s. By which name is this andolan known as?

(A) Amritadevi Andolan

(B) Vankatai Andolan

(C) Prakruti Samrakshan Andolan

(D) Chipko Andolan VIEW SOLUTION
• Question 23
Thermal conductivity of standard SWNT long its length is __________ $\frac{\mathrm{Watt}}{\mathrm{m}.\mathrm{K}}$

(A) 3500 Watt/m.K

(B) 35,000 Watt/m.K

(C) 350 m.K/Watt

(D) 3600 Watt VIEW SOLUTION
• Question 24
By which name is nanotechnology known for its higher performance?

(A) Modern technology

(B) Ideal technology

(C) Engineering Technology

(D) Green technology VIEW SOLUTION
• Question 25
In which direction the incident ray shown by → in the following figure, will go after reflection?

(A) Passes through pole of mirror

(B) Comes back in the direction of incident ray

(C) Passes through the focal point of mirror

(D) Becomes parallel to principal axis VIEW SOLUTION
• Question 26
For which of the following the total internal reflection of light is possible?

(A) Angle of incidence = Critical angle

(B) Angle of incidence is less than critical angle

(C) Angle of incidence is more than critical angle

(D) Angle of incidence – Angle of refraction VIEW SOLUTION
• Question 27
Gita arranges some mirrors in group – 1 and group – 2 according to the magnification, type of image and size of image from the following data.  Sr. No. Group – 1 Group – 2 (1) m<1 and negative real, inverted and small (2) m>1 and positive real, inverted and enlarged (3) m>1 and negative virtual, erect and enlarged (4) m<1 and positive virtual, erect and small

For which of the pairs from the group 1 and 2 you disagree.

(A) 1 and 3

(B) 2 and 3

(C) 3 and 4

(D) 1 and 2
VIEW SOLUTION
• Question 28
Which colour of light is scattered the most (maximum) in the atmosphere?

(A) Red

(B) Yellow

(C) Blue

(D) Green VIEW SOLUTION
• Question 29
In the following figure, which colours should be there in number 1 and 2, respectively?

(A) Yellow and Blue

(B) Blue and Yellow

(C) Yellow and Cyan

(D) Cyan and Yellow VIEW SOLUTION
• Question 30
What is the unit of electric charge in SI system?

(A) Coulomb

(B) Volt

(C) Watt

(D) Ampere VIEW SOLUTION
• Question 31
What is used as anode in Volta’s cell?

(A) Zinc plate

(B) Copper plate

(C) Carbon rod

(D) Iron plate VIEW SOLUTION
• Question 32
The connection of resistances is divided into two groups as follows.  Group – 1 Group – 2 • The resistances are connected in series such that same (equal) electric current flows through each resistance. • The resistances are connected in parallel. So that the voltage drop through each resistance is same. • Equivalent resistance is more than every resistance connected in series. • Equivalent resistance is smaller than every resistance connected in parallel.

Which of the following is not true?

(A) The use of group – 2 connection is to increase the resistance of circuit.

(B) If we connect group – 2, the equivalent resistance obtained is, $\frac{1}{\mathrm{R}}=\frac{1}{{\mathrm{R}}_{1}}+\frac{1}{{\mathrm{R}}_{2}}+...+\frac{1}{{\mathrm{R}}_{\mathrm{n}}}$

(C) The use of group – 1 connection is to increase the resistance of the circuit.

(D) The use of group – 1 connection is to decrease the resistance of the circuit. VIEW SOLUTION
• Question 33
On which factor does the resistance of a conductor not depend upon?

(A) Volume of conductor

(B) Length of conductor

(C) Area of cross section of conductor

(D) Material of conductor VIEW SOLUTION
• Question 34
Who gave the law of electromagnetic induction?

(A) Oersted

(B) Faraday

(C) Volta

(D) Ampere VIEW SOLUTION
• Question 35
How many times does an AC electric current of frequency 50 Hz change its direction?

(A) 25

(B) 50

(C) 100

(D) 200 VIEW SOLUTION
• Question 36
The figure showing Fleming’s left hand rule is given. Which finger or thumb shows the direction of flow of electric current?

(A) First finger

(B) Second finger

(C) Thumb

(D) Small finger VIEW SOLUTION
• Question 37
In which of the following statements the word light year is used correctly?

(A) Light travels with the speed of 1 light year in the Universe.

(B) Cetus dwarf galaxy is 2.46 million light year away from us.

(C) The next complete solar eclipse will be seen after 32 light year.

(D) The Earth takes 365 days to complete the distance of 1 light year around the Sun. VIEW SOLUTION
• Question 38
What is the distance of geo-stationary satellites from the Earth?

(A) 37,956 km

(B) 35,786 km

(C) 43,000 km

(D) 23,123 km VIEW SOLUTION
• Question 39
In the accident of which space shuttle, Kalpana Chawla died?

(A) Columbia

(B) Challenger

(C) Discovery

(D) Atlantis VIEW SOLUTION
• Question 40
Which of the following statement is true for “black hole”?

(A) It emits radiations in large number.

(B) Its temperature is directly proportional to its density.

(C) Its temperature is equal to the temperature of the Sun.

(D) Its temperature is inversely proportional to its density. VIEW SOLUTION
• Question 41
What is true for acidic aqueous solution?

(A) [H3O+] = 10−7 M

(B) [H3O+] < 10−7 M

(C) [H3O+] > 10−7 M

(D) [H3O+] < [OH] VIEW SOLUTION
• Question 42
What is formed by the reaction between metal oxide and water?

(A) Acid

(B) Base

(C) Salt

(D) Metal VIEW SOLUTION
• Question 43
The student of a class discuss about acid base rule as follows.
Student - 1: A substance which donates proton to other substance is an acid.
Student - 2: A substance which accepts proton from other substance is base.
Student - 3: OH ion is not formed in NH3; therefore, it may not be a base.
Student - 4: OH ion is not formed in NH3, then also it is a base.
Who is wrong in this group discussion?

(A) Student - 1 and Student - 2

(B) Student - 3 and Student - 4

(C) Only Student - 3

(D) Only Student - 4 VIEW SOLUTION
• Question 44
An ant has biten Khushi while she was playing. She is feeling burning sensation. Which acid may have entered her body?

(A) Formic acid

(B) Melitin

(C) Benzene

(D) Tenin VIEW SOLUTION
• Question 45
By which reaction metal is obtained from metal oxide?

(A) Liquefaction

(B) Reduction

(C) Calcination

(D) Roasting VIEW SOLUTION
• Question 46
Which of the following substances is hygroscopic?

(A) Cryolite

(B) Feldspar

(C) Anhydrous calcium chloride

(D) Slag VIEW SOLUTION
• Question 47
What is the molecular formula of Calcium hydride?

(A) CaH2

(B) CaH

(C) Ca2H

(D) Ca2H2 VIEW SOLUTION
• Question 48
With which of the following, carbon does not react?

(A) Dilute hydrochloric acid

(B) Dichlorine gas

(C) Dioxygen gas

(D) Dihydrogen gas VIEW SOLUTION
• Question 49

Which of the following works as a catalyst?

(A) Al2O3

(B) K2O

(C) Fe

(D) V2O5 VIEW SOLUTION
• Question 50
Which of the following is a weak bleaching agent?

(A) Concentrated sulphuric acid

(B) Dihydrogen gas

(C) Sulphur

(D) Sulphur dioxide VIEW SOLUTION
• Question 51
Give four examples of uses of nanostructure in History.            [2]

OR

‘Carbon forms backbone of biology of life on earth’. Justify. VIEW SOLUTION
• Question 52
Write Faradays laws of electrolysis.         [2] VIEW SOLUTION
• Question 53
Write the physical properties of ethene gas.          [2]

OR

Explain the preparation of ethene gas by dehydration, giving chemical equations. VIEW SOLUTION
• Question 54
What is lymph? Explain its constitution.               [2] VIEW SOLUTION
• Question 55
Describe the types of biodegradable waste giving examples.             [2] VIEW SOLUTION
• Question 56
Write a brief note on ‘Nakshatras’.               [2] VIEW SOLUTION
• Question 57
What is reflection? Give two examples.               [2] VIEW SOLUTION
• Question 58
How many times more acidic will be the aqueous solution having 2 pH compared to that having 4 pH.             [2] VIEW SOLUTION
• Question 59

Write any two points of differences between, Homologous organs and Analogous organs.             [2]

OR

What is heredity? Explain. VIEW SOLUTION
• Question 60
Write the importance of forests.               [2] VIEW SOLUTION
• Question 61
What is looming? How is it formed? Explain with figure.            [3] VIEW SOLUTION
• Question 62
Explain the construction and working of electric bell with figure.                  [3]

OR

Explain the characteristics of magnetic field lines with figure. VIEW SOLUTION
• Question 63
Write the uses of dihydrogen gas.            [3] VIEW SOLUTION
• Question 64
Explain the modern method of industrial production of acetic acid. Also write any two properties and uses.          [3]

OR

What is soap? Explain the preparation of soap giving chemical equation. VIEW SOLUTION
• Question 65
What is vegetative propagation? Explain Vegetative propagation in Bryophyllum with figure.         [3] VIEW SOLUTION
• Question 66
Explain refraction of light and lateral shift using a rectangular glass slab with figure.          [5] VIEW SOLUTION
• Question 67
Describe reactivity series of metals. Also describe an experiment to decide the order of reactivity of Fe, Cu and Ag.        [5]

OR

Explain Hall-Heroult method of obtaining pure aluminium from alumina with figure. VIEW SOLUTION
• Question 68
What is respiration? Explain the types of respiration.             [5]

OR

Answer as directed:

(a) What is the role of hydrochloric acid in our stomach?

(b) What is the function of enzymes in the human digestive system? VIEW SOLUTION
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