Q1
mcq
1 mark
When lead nitrate powder is heated in a boiling tube, three substances are produced. These three substances are:
- A. $\mathrm{PbO},\ \mathrm{NO}$ and $\mathrm{O_2}$
- B. $\mathrm{PbO_2},\ \mathrm{NO}$ and $\mathrm{NO_2}$
- C. $\mathrm{PbO},\ \mathrm{NO_2}$ and $\mathrm{O_2}$
- D. $\mathrm{PbO_2},\ \mathrm{NO_2}$ and $\mathrm{O_2}$
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Q2
mcq
1 mark
A few drops of turmeric solution are added to a colourless liquid. If the liquid becomes red, the liquid may be:
- A. Hydrochloric acid
- B. Distilled water
- C. Ammonium hydroxide
- D. Lemon juice
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Q9
mcq
Olfactory receptors are able to detect :
- A. touch
- B. taste
- C. smell
- D. light
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Q10
mcq
The movement of sunflowers is in response to a stimulus such as :
- A. gravity
- B. chemicals
- C. day or night
- D. water
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Q11
mcq
Select the correct statements regarding the cross between a pure tall pea plant and a pure short pea plant in Mendelian experiments :
I. For the same trait, two copies of genes are present in individuals that reproduce sexually.
II. The tall plants of $F_1$ generation were exactly the same as the tall plants of the parent generation genetically.
III. One-quarter of the plants of $F_2$ generation were short.
IV. Traits like tallness and shortness both were inherited in the plants of $F_1$ generation.
- A. I and II
- B. II and III
- C. I, II and III
- D. I, III and IV
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Q12
mcq
In plants, waste products like resins and gums are stored in :
- A. leaves that fall off
- B. old xylem
- C. phloem
- D. cellular vacuoles
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Q13
mcq
The image formed by a concave mirror of focal length 50 cm is real and of magnification $-1$. In this case the distance between the object from its own image is :
- A. 50 cm
- B. 100 cm
- C. 200 cm
- D. Zero
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Q14
mcq
When too many electrical appliances are connected to a single socket in a domestic circuit :
- A. total resistance of the circuit increases.
- B. current in the circuit decreases.
- C. short circuiting occurs.
- D. current in the circuit increases.
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Q15
mcq
Amongst the following groups of materials the group which contains only biodegradable materials is :
- A. Polythene, Soap, Wool
- B. Plastic, Leather, Grass
- C. Glass, Aluminium, Neem leaves
- D. Wood, Leather, Paper
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Q16
mcq
Consider the following statements :
I. Every step in a food chain is called a trophic level.
II. Decomposers convert complex inorganic matter in dead remains of organisms into simple substances that go into the soil.
III. In a food chain, energy level increases from lower trophic level to higher trophic level.
IV. Linkages between various food chains constitute a food web.
The correct statements is/are :
- A. I only
- B. I and IV
- C. I, II and IV
- D. II and IV
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Q17
mcq
Assertion (A): Soap does not form a lather with hard water.
Reason (R): Hard water contains salts of calcium and magnesium which react with soap to form insoluble precipitates (scum).
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
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Q17
mcq
Assertion (A): Soaps do not form lather (foam) with hard water.
Reason (R): Hard water has calcium and magnesium salts dissolved in it which on reacting with soap form scum.
- A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
- C. Assertion (A) is true, but Reason (R) is false.
- D. Assertion (A) is false, but Reason (R) is true.
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Q21
short answer
2 marks
A metal exists in nature in the form of common salt. Name the metal. Give reason why this metal cannot be obtained from its compounds by heating with carbon. Name the method by which it is obtained from its compound.
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Q22
short answer
2 marks
Draw a labelled ray diagram to show the formation of image due to a concave mirror when an object is placed between its pole and principal focus.
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Q23
short answer
2 marks
(a) Draw a ray diagram to show the formation of a rainbow in the sky. Mark on the diagram three points A, B and C as given below:
A – where dispersion of light occurs
B – where internal reflection of dispersed light occurs
C – where refraction of dispersed light occurs
OR
(b) Name the muscles present in the human eye which enable it to focus on objects at varied distances (i.e., distant as well as nearby objects). Explain how it happens.
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Q24
short answer
2 marks
(a) In the diagram given below, name the labelled parts X and Y. Mention one function for each.
OR
(b) Name the parts of the nervous system which are involved in the following activities:
(i) Maintaining body posture
(ii) Salivation
(iii) Hunger
(iv) Answering a question
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Q25
short answer
2 marks
List two ways due to which variations arise in a population. State the importance of variation.
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Q26
short answer
2 marks
Explain why a garden is called an ecosystem.
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Q27
short answer
3 marks
Write one chemical equation each for the reactions in which the following changes occur, specifying the change observed:
(a) Change in colour
(b) Change in temperature
(c) Formation of precipitate
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Q28
short answer
3 marks
(a) A chemical compound which is obtained from baking soda is used in glass, soap and paper industries. Identify the compound. How is this compound obtained in its crystalline form? State whether this compound is acidic/basic/neutral in nature. Justify your answer.
OR
(b) When electricity is passed through an aqueous solution of common salt, three products are obtained. Name them, specifying the electrode at which each of these products is obtained. Also give one use of each product.
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Q29
short answer
3 marks
In the given circuit when key is closed, determine the following:
(i) Total resistance offered by the three resistors
(ii) Reading of the ammeter
(iii) Reading of the voltmeter
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Q30
short answer
3 marks
What is the probability of a male child or a female child being born in case of human beings? Explain.
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Q31
short answer
3 marks
(a) Name a part of the flower which (i) persists even after a fruit is formed, (ii) attracts insects for pollination, (iii) produces pollen grains and (iv) changes into seed after fertilisation.
(b) After pollination, how does a male germ cell reach the ovary? Mention the significance of this event.
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Q32
short answer
3 marks
(a) Draw the pattern of magnetic field lines around a current carrying straight conductor through which current is flowing vertically upward. Mark the direction of the field lines corresponding to the direction of current in the conductor.
(b) An alpha
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Q32
short answer
3 marks
(a) Draw the pattern of magnetic field lines around a current carrying straight conductor through which current is flowing vertically upward. Mark the direction of the field lines corresponding to the direction of current in the conductor.
(b) An alpha particle enters a uniform magnetic field at right angles to it as shown in the diagram.
(i) Name the rule which can help in determining the direction of force acting on the alpha particle in this case.
(ii) Apply this rule and find the direction of force on the alpha particle.
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Q33
short answer
3 marks
Draw a ray diagram to show the refraction of a ray of light through a triangular glass prism and mark on it (i) angle of incidence ($i$), (ii) angle of emergence ($e$), and (iii) angle of deviation ($D$). What would happen, if instead of a ray, a beam of white light falls on the prism ? Give reason for the phenomenon that occurs in this case.
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Ethanol (commonly known as alcohol) is an important carbon compound widely used in industries, hospitals, etc. Because it is a very good solvent, it is used in medicines such as cough syrups, tincture iodine and many tonics. As it is a cleaner fuel, ethanol is used as an additive in petrol in most of the developed countries of the world.
Q34
long answer
5 marks
(a) (i) Write the relation between the electrical resistivity $r$ and the resistance $R$ of a cylindrical conductor of length $l$ and area of cross-section $A$. Use this relationship to determine the SI unit of $r$.
(ii) Find the electrical resistivity of the material of a wire of length 120 cm and diameter 0.4 mm. The resistance of this wire is 3 $\Omega$.
OR
(b) (i) What is meant by heating effect of electric current ? Derive an expression for the amount of heat produced in a conductor of resistance $R$ through which a current $I$ flows for a time $t$.
(ii) Calculate the amount of heat produced in a conductor of resistance 10 $\Omega$ through which a current of 2 A flows for 100 seconds.
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Q34
short answer
1 mark
Name the products formed when ethanol burns in sufficient air (oxygen).
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Q35
short answer
5 marks
(a) Study the following flow chart showing the breakdown of glucose by various pathways. In this flow chart, in four blocks some blanks are given as A , B , C and D .
(i) Write the names of A , B , C and D .
(ii) Write the source of glucose molecule involved in cellular respiration in (I) plants, and (II) animals.
(iii) Why do athletes sometimes suffer from muscle cramps during running ?
(iv) Give reason why the rate of breathing in aquatic organisms is faster than in terrestrial organisms.
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Q35
short answer
2 marks
State what happens when 5% solution of alkaline potassium permanganate is added to warm ethanol. Draw the structure of the product formed and state the role of 5% solution of alkaline potassium permanganate in the reaction.
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Q36
short answer
5 marks
36. (a) Write electronic configurations of two elements X (At. no. 12) and Y (At. no. 17). Show the formation of ionic compound when X and Y combine with each other. Write the name and formula of the compound formed. State what would happen if electric current is passed through the aqueous solution of this compound. Name the ion that will reach at (i) cathode, and (ii) anode.
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Q36
short answer
5 marks
36. (b) (i) Write the name of two metals of moderate reactivity. Which one of the two is more reactive ? How can this fact be demonstrated experimentally in a school laboratory?
(ii) Some metals of moderate reactivity are also found in the Earth’s crust in the form of their carbonates. Name the processes involved in the extraction of metal from them, giving chemical equations for the reactions that occur.
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Q36
short answer
2 marks
State what happens when ethanol is heated with excess conc. $\mathrm{H_2SO_4}$ at 443 K. Draw the structure of the product formed and state the role of conc. $\mathrm{H_2SO_4}$ in the reaction.
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Q37
short answer
1 mark
37. Ethanol (commonly known as alcohol) is an important carbon compound widely used in industries, hospitals, etc. It is a saturated carbon compound and a good solvent. Due to these properties, it is used in drugs, tincture iodine, etc. Being an important fuel, its use leads to the need for more plants in many developing countries.
(a) Write the structure of ethanol.
(b) What happens when ethanol reacts with oxygen? Name the products formed.
(c) (i) What happens when ethanol is mixed with 5% solution of potassium dichromate? Write the structure of the product formed and mention the role of 5% potassium dichromate solution.
OR
(c) (ii) State what happens when ethanol is heated with concentrated $\mathrm{H_2SO_4}$ at 443 K. Draw the structure of the product formed and mention the role of concentrated $\mathrm{H_2SO_4}$ in this reaction.
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Plantation drives are often carried out especially during monsoon season for the protection of our environment. Such programmes need a lot of saplings for tree plantation. Plants are propagated by sexual or asexual means in fields and nurseries. Over the years horticulturists have developed asexual methods that use vegetative parts of the plants to multiply. Many plants can reproduce by this method naturally as well as by artificial means.
Q37
short answer
1 mark
Which specific part of the plant is used for sexual and asexual means of propagation to produce a new plant?
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In our laboratories we use compound microscopes to see the magnified image of a microscopic object. A compound microscope is made up of two lenses. The lens nearest to the object to be viewed, called objective lens, forms real, inverted and magnified image of the object. This image serves as an object for the second lens called eyepiece. The eyepiece forms virtual, erect and magnified image of its object. Thus, the resultant image formed by a microscope is virtual, inverted and magnified with respect to the microscopic object viewed.
Q38
short answer
1 mark
The image of an object formed by a convex lens of focal length 2 cm is real, inverted and magnified. What is the range of object distance in this case?
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Q39
short answer
1 mark
Give one example of (i) a flower, and (ii) a fruit grown by vegetative propagation.
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Q39
long answer
In our laboratories we use compound microscopes to see the magnified image of a microscopic object. A compound microscope is made up of two lenses. The lens nearest to the object to be viewed, called objective lens, forms real, inverted and magnified image of the object. This image serves as an object for the second lens called eyepiece. The eyepiece forms virtual, erect and magnified image of its object. Thus, the resultant image formed by a microscope is virtual, inverted and magnified with respect to the microscopic object viewed.
(a) The image of an object formed by a convex lens of focal length 2 cm is real, inverted and magnified. What is the range of object distance in this case ? 1
(b) The image of an object formed by a convex lens of focal length 6 cm is virtual, erect and magnified. What is the range of object distance in this case ? 1
(c) (i) An object is placed at a distance of 12 cm from the optical centre of a convex lens of focal length 18 cm. Draw a labelled ray diagram to show the formation of image in this case. 2
OR
(c) (ii) The image formed by a convex lens is real, inverted and of the same size as the object. If the distance between the objects and the image is 60 cm, determine the focal length of the lens. Give justification for your answer. 2
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Q40
short answer
2 marks
List two advantages of growing plants by vegetative propagation.
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Q41
short answer
2 marks
Describe an activity to show how potatoes reproduce asexually.
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